something rudefyet said about turbochargers..\Power Upgrades

[DaveFromColorado]

I'll start off by saying I don't want to start a fight about turbochargers, I'd just like to add a little real world exiprence to the conversation - that being said:

 

 

["rudefyet"]I'm studying a book right now on turbocharging...and well...it's almost impossible to acheive full boost in first gear...that being said...a turbo does't give peak performace till 2nd gear...so a good ol V8 would still have an advantage since it has more tq in 1st gear

 

I'd like to say that this is only sometimes the case, you have to remember there's gearing, engine sise, turbocharger size, turbocharger selection (ceramic, ball bearing's things like that), timing, fuel delivery and so many other factors involved. case in point, my Mustang, 1st gear, 3k RPM's, I've got full boost (~28lbs) all the way up to 7500 RPM's, the 3000 GT VR4 that was wrecked would have 22lbs of boost from 3800 RPM's to redline (7000 rpms) , in first gear, so you can't say that it's impossible, you would really have to put together a good turbocharger/engine combo if you wanted to take advantage of a boosted engine. It's one thing to read in a book about it, it's an other to modify a a car to make these things work.

 

the other thing to look at is sequential turbochargers, or twin turbochargers - those are designed to make the turbo lag nearly gone, and you can see those perform well in first gear, but again, that goes along with the turbocharger/engine combo decisions that need to be made.

 

--Dave

[rudefyet]

oh well looks like i got a lot of learning to do

[DaveFromColorado]

I'd have to say, I've read books about turbochargers, and they are a GREAT place to start off, but I worked at a high performance shop for 2 years, and learned a LOT more about them, with just seeing real world stuff come to life in projects that I worked on, and that other people worked on and brought in, it takes LOTS of time to learn stuff like that because there's SO many factors.

 

Here's a helpful hint to anyone who's got a turbocharged engine, you want your exhaust to flow as close to the same numbers as the intake, such as (pullin' numbers outa my ass here)

 

let's say your intake flows 100 CFM, most engines will have the exhaust only flowing 70% of that or 70 CFM, great for naturally aspriated enignes, where as with turbochargers, because you have so much backpressure from the turbin housing itself, you want to flow more exhaust out of the engine, currently my exhaust in my mustang is flowing 96% of the intake (couldn't port it any further then that) and I have CRAZY turbo power in the low end (16lbs of boost at 2k RPM's) just a note for anyone who's getting their heads ported, make sure, turboheads need to be on a flow bench, as you want the calculations as close as you can get them.

 

--Dave.

[god910]

Dave, I have been going over this in my head recently. It's good to see a discussion started about this. One of the first things people think about when they think performance is: MORE AIR. Well, in the case of our TGP's it's a really bad idea, mainly because where's it gonna go??? We can barely get out the air we have let alone get a bigger T/B, ported heads/intakes, bigger valves, etc... Since the TGP's run over 2:1 pressure ratio, we all need to consider exhaust work first. (Being manifolds, x-over, TURBO (That's a big one), and downpipe.) The rest is easy, but we need to get something started w/ the manifolds and work our way back. Anyone w/ flowbench experience, can the manifolds be flowed??? I have an extra (If you want to call it that) engine w/ manifolds that I will be porting out, but would like to be able to directly correlate stock flow vs. ported flow vs. pressure ratio differential. (Getting a ratio w/ both) I think this would be a good place to start. Ideas? I'll have to get w/ my machine shop and see what we can work out.

[DaveFromColorado]

Alrighty, lemme see if I can answer a few of these things right off the bat, or explain them real quick...

 

MORE AIR is a good thing in all cars, the TGP's already have this, as they are forcing air into the engine with the turbocharger, so this is covered.

 

as for the exhaust -

 

Since you've got so much backpressure between the engine and the turbocharger you typically don't want any backpressure behind the turbocharger, now this is correct to a point (granted I've said no backpressure on the turbo is best) now I'll take the Eclipse for my example this time, any of the high performance eclipse's out there running VERY large exhaust's after the turbocharger have a problem called "boost creep" where the boost will start climbing even tho the wastegate is wide open. This is from is when the exhaust flowing more freely through the turbocharger and two things happening, 1) no backpressure on the turbin allowing it to spin much faster, and 2) the rather small area provided as the bypass (wastegate) cannot flow enough exhaust to slow the turbin down. this is why you will often see "External Wastegates" on a lot of those cars, they provide a MUCH larger area to bypass the exhaust.

 

as for a Larger supply from the engine to the turbocharger is always* a good thing, the faster you can get it there, the better.

 

Turbochargers also use the heat from the exhaust, so wrapping everything in a good heat wrap is a positive way to keep the exhaust moving towards the turbocharger and also taking advantage of the heat.

 

for the TGP's I'd HIGHLY recomend larger intercoolers, hell, for nearly ALL turbocharged applications I'd recomend it, so maybe not always more boost, but colder air is more dense and will provide a much more positive effect on the power of the engine then simply raising boost and heating up the air more. remember, air heats up as it's compressed.

 

if you went with a larger TB, that'd help throtle response on the low end, but on the high end, you'd find that your exhaust will still have you traped. Smoothing all the edges, and gasket matching everything is a VERY smart idea as it will decrease the turbulance in the manifold and allow more air into the cylinders. also, polishing the internal area of the upper intake manifold should help, as you are not introducing fuel in this area so you don't have to worry about it puddeling up in there.

 

as for the exhaust manifolds ... yes, you can flow the exhaust manifolds.

 

the way that we were flowing them at the machine shop that I work with is to have it drawing out of the largest area (or the part that would hook up to the turbocharger/X-over pipe) and first see if you have enough flow to get the numbers of all three ports at the same time, (some benches can't flow that much air to reckognize a restriction) then cover two of the ports from the cylinders at a time, and then move on to the next port, after you've recorded all your numbers, you can then start the grinding processs.

 

Also, remember if this is for a turbocharged aplication, the manifolds have to endure extreme heat (1500+ degrees fahrenheit ) so removing too much material could be a VERY bad thing.

 

now I'm not 100% sure what you mean by pressure ratio differential and before I try to answer that, and end up babbeling, could I get ya to clear that up a little?

 

--Dave

[god910]

I remember Jeff M. saying that wrapping the exhaust on our cars was a bad idea, which seemed like a bad idea to me at the time, but he explained it, and it came clear after that. I will try to find the post. What I meant by pressure ratio differential is just the difference between the pressure ratio of ported exhaust manifolds vs. the pressure ratio with stock unmodified manifolds. And yeah, I didn't mean to say that more air is bad typically, however if you take a stock TGP and go and port n' polish the heads, give it a nasty cam, and port the intakes, it could send the pressure ratio through the roof, making only 6-8 pounds of boost possible due to the grossly ineffecient T-25 turbo. Notwithstanding the fact that 6 pounds of air @ "X" flow is better than 12psi @ a lower flow. But plain and simply, the chip won't give a shit, and still try to give it 11.5 psi. Making the air REALLY hot, and giving gross amounts of KR. I was just getting at the fact that w/ our cars we need to focus on exhaust work before intake work. (Except for the turbo which actually is a double edged sword when discussing intake and exhaust.) Gotta go to bed, but hopefully will be able to find the post from Jeff in the morning.

[rudefyet]

hmmm....got a few questions off the top of my head....the whole boost only in first gear thing i had assumed...it wasn't really a fact i read

 

but i do recall two things i did read...mind you i just finished the first chapter and by no means an expert

 

the smaller the turbo the more backpressure it will create...ok not sure where i was going with that yet

 

but the main thing was the cold air idea...you said something about wrapping the exhaust pipe with insulation...my thought was that turbos are more efficent with colder air...wouldn't more heat from the exhaust heat up the air flowing through the turbo more? but then agian...what about the turbo's cooling system...not sure if i understand what that does yet

 

I agree with the bigger intercooler...the cooler air is more dense (not sure how denseness contributes to the engine yet)...but cooler air will decrease chances of detination from the increased pressure...because increased pressure = increased heat...so colder air allows for higher boost levels

 

Just random babbling now...i plan to make my own turbo kit or modify the exsisting depending on what kind of car i get...i have a good idea how i'll do it if i get a TGP...i'm still looking though to figure out which size turbo i should choose for me and how i'm going to assemble and set up everything...the book will help me out alot but the car itself is the true experience

[DaveFromColorado]

... as for exhaust wrapping...

 

I'd imagine the manifolds can't handle it, and will start to crack under the extreme heat and inability to cool themselves using the ambient air, that's why the TGP's are bad for exhaust wrap (just a guess, but it makes perfect sense) plus some turbochargers can't take the heat, and you see the turbin's "meltdown" or start breaking apart and being sent down the exhaust.

 

the reason the theory is good: when wrapping the exhaust side of the turbocharger, the heat is forced towards the turbin which in turn makes it more efficent it will be due to the fact it will be not only using the flow of the exhaust, but the heat from it as well. Also it will help with underhood tempatures, as the heat will be traped in the pipe, rather then heating up the engine compartment.

 

okay, when talking flow vs. pressure that's a whole different story, if you have a turbocharger that can flow (numbers outta my ass again) 300 cfm at 6lbs of boost, and an other turbocharger that can flow 400 cfm at 6lbs of boost the one that flows the 400 will push cooler air, but at the same time, it will take longer for the turbocharger that pushes 400cfm to reach that level. Smaller turbochargers will heat up the air to the point where it expands creating what looks like boost, and this is where you get your pressure drop across the intercooler, but they will spool up sooner.

 

I think I understand what you mean with the pressure ratio differential, but I don't know how to answer those questions, I'll be stopping at the machine shop on monday to find out those answers for you.

 

Cooler more dense air helps a lot with performance due to a couple things, the first more dense cold air will have more oxygen molicules per cubic inch, where as hotter air will have less. Also, with extreme heating of the intake charge this can push the cylinder tempatures up which can in turn preignite the fuel causing knock.

 

I think one of the best things that can be done to the TGP's is exactly what god910 was saying - more open exhaust, from the valve to the ass of the car, this will increase performance more then you can imagine, plus if you've got a really open exhaust from the valve to the turbocharger, you can get away with a much larger turbo, keep the 11.5 lbs of boost, but it'd be so much colder that you'd have way more power then if you took your 11.5 and doubled it with the stock turbo.

 

intercooler upgrade, intercooler upgrade, interrcooler upgrade - I can't stress that enough, I wish I could run an intercooler, but my 'stang's setup won't allow it.

 

you could always do the mean trick I'm doing, run N2O thru the engine, nothing big, just a little 10hp shot in the intake right before the TB active only at WOT, it's not enough N2O to add power, but it will freeze the intake charge and increase performance.

 

I'll write more when I've got the info about the pressure ratio differental.

 

--Dave

[rudefyet]

ah i see...i didn't understand the difference in turbo sizes that a bigger turbo would produce more cfm the a smaller one...makes a lot more sense now

 

i see why a turbo upgrade on a tgp is so important now...because with a larger turbo you can run the same boost...but more air will be flowing into the engine

 

so just one more question...say i'm running 12psi of boost on a small turbo (i'll make up numbers too) and it's pushing 300cfm...i upgrade to a larger turbo run the same 12psi but it's putting out 400cfm...will the larger movement of air from the bigger turbo increase the cylinder pressure/heat or will it stay the same just like the psi?

 

now all i gotta do is figure out the best turbo for movement of air...that won't take to long to spool up on a 3.1

[DaveFromColorado]

yes, it will increase cylinder pressure, and some* heat, being as the charge is already cooler that will significently help.

 

--Dave

(msn: davefromcolorado@hotmail.com)

[Guest TurboSedan]

Smaller turbochargers will heat up the air to the point where it expands creating what looks like boost, and this is where you get your pressure drop across the intercooler, but they will spool up sooner.

 

 

--Dave

 

not sure if i understand this statement, can you elaborate? i know a smaller turbo spools quicker, and that even tho it might crank out 'X' amount of PSI doesn't mean that it will flow the same as a bigger turbo at the same PSI, but what does that have to do with the intercooler? specifically pressure drop across the intercooler?

 

also, why nitrous? why not alcohol or even water injection?

[DaveFromColorado]

what happens with a turbocharger is it reaches it's limit of how much air it can push, once you go beyond that point it just heats the air to extremely high tempatures (400 degrees anyone) and the heat will cause the air to expand, and the expansion of the air will show higher numbers on your boost gauage, your map sensor, or whatever else you are taking a reading with.

 

You can use alcohol injection, or water injection, both will cool the charge, but being as N2O comes out at an extremely cold tempature it will cool the charge temp very quickly - but I can't remember the actual tempature the N2O comes out as.

 

on the 3000 GT we would run propane, as it will do the same thing as the nitrous, but it's also a combustable fuel so that will add to the antiknock octane rating of your gasoline (meaning you can run cheap gas at high boost levels)

 

I know a guy who uses a water/alcohol mixture to cool his charge tempatures and it works very will for him, he's quite happy with it.

 

I'm using N2O because I'm going to run a much larger shot of N2O to make up for what boost lag I do have (up to 3K rpm's)

 

--Dave

[Guest TurboSedan]

i know that a smaller turbo needs intercooling due to it compressing the air to the point flow doesn't increase but PSI does, and it gets very hot.

 

Smaller turbochargers will heat up the air to the point where it expands creating what looks like boost, and this is where you get your pressure drop across the intercooler, but they will spool up sooner.

 

i guess i took your statement to mean that pressure drop across the intercooler was due to running too small of a turbo. i always thought of 'pressure drop across an intercooler' as being dependant solely on the design of the intercooler itself, IOW you would see the same pressure drop across the intercooler no matter what turbo was pushing the air thru it, no matter what CFM or PSI.

[DaveFromColorado]

I should've phrased it differently.

 

you will always see a pressure drop across the intercooler because as the air cools and becomes more dense, the pressure will drop, but the ammount of air entering the engine will remain the same.

 

(sound better?)

 

--Dave.

[Guest TurboSedan]

lol thanks, sorry if i was sound like i was nit-picking, i just want to get this stuff straight in my head

[DaveFromColorado]

it's no problem, this is why I try to re-read my posts, but often forget and just post 'em right away...

 

it's also how my spelling errors all come out

 

--Dave.

[Guest TurboSedan]

gotta question...

 

with the TGPs stock unmodified pistons, stock CR, stock unmodified heads, etc, is it even possible to run 15-20 psi without detonation, even if say you were running a larger more efficient turbocharger with adequate fueling and good intercooling? IOW, does the TGP engine have such a low detonation threshold as is that in order to run above 15psi, you would need to run lower compression pistons or improve upon the combustion chamber and/or piston design first?

[DaveFromColorado]

wow, there's a question I don't know if I'm totally qualified to answer, but I can say, if you've got a good turbocharger, and correct fueling, then you shouldn't have a problem, but you may need to run a higher octane gasoline.

 

but again, I don't know the TGP enignes that well, I'm working off of general knowledge of turbocharged engines.

 

--Dave.

[Guest TurboSedan]

i just think that if i did use a larger turbo, big FMIC, bigger injectors etc that it would only be a matter of time before i wanted MORE ecspecially if running above 14.7 psi (2-bar) was possible without detonation. i know a 3-bar calibration isn't available for the TGP, but you could still use a ziener diode or a custom chip with no overboost cut and run above 14.7 psi so long as you had enough fuel to support it of course.

 

if you could raise the detonation threshold (of the TGP engine) by upgrading to a larger more efficient turbo, big FMIC + alcohol injection and high octane gasonline, i would want to milk the shortblock for all it's worth, up to the detonation threshold and/or up to the point where i started melting pistons if the above mentioned mods could get the TGP into the high 12s at only say 14 psi, that would be great, but if it took more PSI to go high 12s i would hope the stock TGP shortblock would allow it.

 

i'm getting worried that running even mid 13's is barely possible without major internal engine work/mods :? i'm even starting to lose interest in the TGP because it almost seems like it is impossible to make one run fast, like it's a lost cause to even begin trying to modify one and make it fast due to the overall engine design prohibiting it

[DaveFromColorado]

the first mods to my 'stang were to raise the boost from (6 psi to 10 psi), run 110 leaded gasoline, retarded the timing 4 degrees, and with those few things alone, still the stock bottom end (9:1 comp ratio) stock head, stock exhaust, stock carb I gained almost 120 hp.

 

--Dave

[Jeff M]

That was me on DP between intake charge to exhaust charge if we call it that. And it’s good to see some level headed thinking and exchanging instead of bashing who knows best, sure as hell makes for some very enjoyable reading hearing people elevate each other with a combined knowledge base!! Sweeeet!!! I totally agree on tons of this, obviously a lot of thinking before speaking going on here, say what you know, ask what you don’t, I am humbled often and enjoy it as it keeps me challenged and open minded to learning more, this is when More is Better!! As for books, the best ones help give formulas to what wrench tuners learned first hand, though best to have both, but a lot of books are from those old guys that put in the time and learned by hand what they wrote in those books ;-). When I started doing turbo work in 1985 on GN/T-Types, then 1990 added the TGPs, then 1992 on Syclones and Typhoons (I can’t stop even today ), I was greatly assisted in those younger years by older guys with great savvy, and books they shared with me (that I soon bought so I could quickly return those books!), and still today I have a few greats that I debate with that keeps that fine edge honed. It still ended up that “in the field†work still had its own twist on the books, but both were instrumental in being successful. THEN……you have and always will have differences in results and beliefs regarding what works for a specific setup, one will think its all about the downpipe, cat, muffler and exhaust pipes, others think it’s a magic cam that will do the trick, and other flavors, until someone does a lot of testing and swapping parts to proof things out for them. Obviously individual OEM turbo setups will respond differently to the same efforts, depending on the “setup†and the weakest links such as one having a too small a turbo, another too small a intercooler etc. Some turbo setups have damn good turbo size that only needs some exhaust work to kick up the boost (assuming fueling and timing is happy) and an air filter upgrade to get great gains, assuming “good†is knocking off a 1 to 1.5 seconds off your ets. Other setups may need more work in more than one area, AND like Dave says, what are the ones that need the help, and how much help, no sense have one item upgraded or vastly upgraded if there are a number of lame pieces negating your efforts/$$ It’s a lengthy and expensive process to find the level of each item stock then modified to balance each as a match/kit for max power i.e. air filter, turbo compressor side, intercooler, TB, intake, cams, headers, xover, turbo exhaust side, downpipe and all till the tips. The best aftermarket companies spend vast amounts of man hours and thousands of bucks testing all of these stock items determining the level of performance for each OEM turbo setup, then deciding which items to upgrade and how much, to balance the kits they offer, it’s a lot of work to get to this point! All too often I have heard from owners and aftermarket companies having someone with Company-X turbo, but Company-Y Heads and Company-Z Cam, resulting at best with poor performance, more than likely a dangerous setup, that’s a lot of time and money wasted, and frustration in the end for both sides. But what happened is too many customers did not want to buy any one supplier’s kit feeling too locked into the supposed supplier’s cornering of the market, or not liking or believing the claim their kit was the best or was that good, when indeed as a package, those upgrade kits were the best in their own right!

 

In the end there were a lot of people that learned the hard way that shared those results on the GN/T-Type/TTA Message Boards as well the SyTy and Moustang and F-Body and many other message boards, without the internet, those companies would NOT have done so well, or their customer ;-).

 

 

I can explain the DP, 2:1 is 20 psi of back pressure at the turbo with 10 psi of boost going into the engine, that is the max limit to shoot for, less is better such as 15 psi of back pressure to the turbo with 10 psi of boost, but will start to take some big work to heads, cams, tuned headers (nothing big or we loose velocity and boost spool-up!) etc to achieve. For now the TGP runs in the 3:1 range and higher when you start to open the heads up (and/or cam), stock the heads only flow 110-113 cfm on the exhaust side, the best worked TGP heads I have heard of flow 161 to 163 cfm and at that point the stock turbo even with a T28 wheel and carved out housing is still a big bottleneck!! And from testing a lot of TGPs and turbos and heads and cams (and a larger xover, nothing gained there) the exhaust housing of the stock or modified TGP is the main culprit period! Even if you knock off 6 psi from the exhaust after the turbo, there is only so much air that will go through this TGP turbo/turbine side, it’s the relationship of cfm coming out of the engine at say 600 cfm being stuck with a turbo/turbine side that only allows 200 cfm, opening up the exhaust after the turbo by 100 cfm will not make the turbo go from 200 up to 300 cfm, it just don’t work that way! The T25 is indeed small for a 3.1L engine, more sized for a 2.2 to 2.4L engine, but GM expected McLaren to send them a setup that would not have any lag issues, and max boost of 8.5 psi, something a T25 can do no problem on the torque long runners/big 3.1L engine (THOSE 2 points each powerful in their own right!). The stock A/R is already bad at .68, larger turbine wheel and larger carving to fit it still does not get us there, we need a larger housing, and just for the record, a .86 A/R on a T25 is not the same as an .86 A/R on a T3 or T4! Some more info is the TGP turbo stock or T28 upgraded has NO LAG to speak of on this 3.1L motor, take out the fuel cut, keep the timing safe/stuff in the octane, unplug the wastegate and you get 10 psi in about 1 second, climbing up quickly to about 13 psi in the blink of an eye, no need to worry about keeping the heat in the headers/x-over/turbine side or wrapping (for cracks yes!), or downpipe/exhaust upgrades, not for a while, or at least until someone has a much larger turbo, but even then the heads will be more they key to exhausting the engine out for a new full charge of fresh air, and in spewing the exhaust out well enough to spool a bigger turbo, lots of balances to look at, and to pick properly from.

 

As for turbo sizing talk, been a while on here since I have seen CFM ratings, nice to see this being used instead of boost/psi ratings. Boost is the air backing up in the intake, effects from the cam, and the heads, not just what is going into the combustions chamber, open up the main restriction/the heads and boost pressure will drop all things being equal, and you also make more power as the turbo works less hard/less heat, and the engine fills faster before the cam shuts things up. CFM actually makes things easier to work with, and we can use it with the rest of things such as air filters upgrades, TB upgrades etc, but I am sure you know that is just the quantity of air not quality of air. Quality of air being its mass, hot-thin air or cold-dense air, that is where the rating (this info is for anyone) of lbs/min comes in and what is used to rate every turbo out there. A 3.1L motor with 85 percent volumetric efficiency needs 25 lbs/min of air to make 10 psi and about 240 hp (with intercooler), the stock TGP turbo does 29 lbs/min/about 12 psi so we can get up to 260 to 280hp depending on outside (260 warm weather, 280 winter weather!) ambient air temps at least! But with injectors gummed up, 100k on fuel pump and/or fuel filter etc etc those hp numbers are pushing it, that is why so many of the GN/T-Type/TTA, SyTy etc owners always get such things up to at least running like new, or take the opportunity to upgrade (not complain lol ).

 

While typing this, I see more questions, so will add what I can. I like this, someone is using advanced thinking…..what if we had a huge mass air flowing turbo, big ass intercooler, tons of fuel, great heads, flowing exhaust (you would need exhaust work then)…what is the max safe power we can make in this motor? Using those old guys like Ryan Falconer and new guys like Curtis Walker running the big numbers highly mod’d, the TGP engine has been run at 350 hp at 8,500 rpms and 13.5:1 compression ratio with a normally aspirated setup, though the crank had to be upgrade at that high a level of rpm, but the engine held for its race seasons. Also hp at 400 plus and 7,500 rpms was run with no engine block failure and repeated runs. Knowing this and what has been written in Chevy Power books, the TGP block can run properly tuned 350 hp at 8,000 rpms for a long time, lower the power band rpms and more power can be safely made (its NOT power nearly as much as rpm that takes out a properly tuned and running engine!!). How much boost/cfm/lbs-min can the block run…the engine has a great heart shaped combustion chamber which helps a lot, along with its aluminum construction, and swirl ports, and relative amount of squish, also the engines 60 degree construction and neutral balance and firing order is all on our side. What starts to limit things for one is the stock pistons expanding too much from the heat of such a large and powerful combustion, running into/scraping the sides of the cylinder walls, stock rings starting to give up, piston pin hole elongating from the stress, and most likely the heads lifting off the block with the weak stretch-to-yield stock head bolts, and an old 100k+ miles/14 year old heads gaskets, but off the top of my head these are only at 350 maybe 400 hp or more, everything very related to how long you think is an acceptable life, and how much of that engine is still stock??? But don’t ask that defining question because I won’t go there .

 

Well its been great reading the other posts, enough to drag me from many other projects, but I am tired and its getting late and my grammar is going to start to sputter/detonate and become less reliable .

 

Jeff M

[DaveFromColorado]

and Jeff M takes the prize for long winded... LOL J/K

 

Awesome information!!

 

allow me to stray for a second - the Mustang I drive is a 1980 Mustang Turbo, with the old carb/turbo setup, it's a draw thru- much like the older t-type/gn/tta's thought I'd mention because you don't see too many of the Carb/turbo's anymore, people all opted for fuel injection.

 

that being said...

 

that's some good information (I can't believe I read the whole thing at 3:55 am)

 

Oh, you said something that made me realize I forgot to mention my golden rule of any automotive work -

 

Tune the thing up, make sure everything is working 100% properly. Fuel Filter, Plugs, Wires, Oil Change, everything, then work on the upgrades.

 

--Dave.

 

p.s. wow that was some really good information.

[TurboGTU]

Fannaly...some flow numbers for the head.

115cfm...thats a joke right...and 160cfm...on a well done ported head...WHAT?...Is this port already hitting the watter jackets. I know I just bearly avoided the jackets by 4mm on the bottom by where it curves to the ports and almost eliminated the valve bump. So I guess im at 140cfm.

I was getting boost creap at about 4600rpm at about 11psi in third doing 80mph with WOT. I ported the wastegate to almost 2mm smaller than the flap and helped it some...so yea...this thing is too small.

On the ford 2.3 the thing flows 150cfm stock and 200cfm ported(they get bigger valves though)..So I guess 50cfm from porting is only possible on the stock heads...well theis two.

What does the 3100s flow?...who gives a dam about the intake side.

Thogh I think only a hand fab intake manafold is possible to flow high hosepower on thies 2nd gen heads.

 

Now about that tranny issue im having...LOL

 

We currently have both engines.. 8) ...so I could relate to you two.

87 ford turbo coupe

and of course the GTU.

[rudefyet]

I've heard it's very possible to run good time with a tgp...stuff like a 3100 tope end swap...a better cam...lighter valves etc...

 

with some good top end work i'd say 12's are doable on a slighty larger turbo...better fuel system and larger intercooler

 

from what i've heard the 3.1 pistons, rods, crank etc. are pretty solid and can handle quite a bit

[god910]

...from what i've heard the 3.1 pistons, rods, crank etc. are pretty solid and can handle quite a bit

Nah, they are made of bubble gum and jelly beans. Dbtk2 (er, whatever it is) is BOUND AND DETERMINED to get his STE into 13's w/ a stock setup, and I by God, can't wait until he does it. I as well think it's possible (but not EASY) I personally don't want to try it, but might be inclined to. If he can't make it. I'm just debating whether I want a 13 second stock auto TGP or not. I really just want a nice show car, and leave the low 1320 times to Sunshine.

 

Here is a possibly stupid question: Would we benifit by not letting all the exhaust gas exit by the turbo OR the wastegate. Perhaps a W/G in the x-over to purge some exhaust prior to the turbo. (Don't think I'm saying installation would be easy or even possible.) I'm just saying, if we had LESS exhaust trying to make it's way out through the turbo, would we be better off? I've got an idea, but if it's retarted, then I'll let it go by the wayside.