turbo Q....quick one!

[Guest TurboSedan]

 

Turbo engines will make boost in nuetral. It is possible, it can and does happen.

 

 

i've seen it happen myself with my brother's Turbo Dodges. hell i can make the BOV in my Cutlass go off if i rev it up quickly in neutral so obviously the intake is seeing some kind of boost. i don't have a boost gauge at the moment so i don't know how high it actually goes. i just asked my brother about his cars and he seems to think he could probably hit "10psi no problem" if he tried (in neutral).

 

futuretgp'er: just because you aren't getting the answers you want doesn't mean you have to be a dick. lighten up or look elsewhere.

[TGPilot]

tgpilot enough questions......if you have something to help out feel free but i don't think what your doing is constructive.......the things you mention like BTU's aren't even relevant.....its a british thermal unit...but it isn't necessary to know what that is to discuss the topic....

you don't know the answer to the first question and you have nothing new to add to the discussion...what point are you trying to make by posting!

 

your using "questions" as a crutch becuase either A: you don't have anything with substance to contribute or B: your too lazy to put in writing what your thinking.....either way your no help so don't play the games....so far you responses have been utterly pointless....it sounds like you haven't even been reading what has been written .

 

 

Ok...the problem is you are not looking at what happens before the turbo and this is what I was trying to spark with your thinking. Obviously this back-fired and you went on a tangent! No surprise there.

 

BTU's has EVERYTHING TO DO with an internal combustion engine. N/A' date=' Turbo'd, or Supercharged. BTU's is heat and more importantly ENERGY! Obviously there is alot of heat generated in an internal cumbustion engine. The higher the BTUs/heat in the cumbustion chamber and the colder the area surrounding the cumbustion chamber to include the intake air coming in, the more power you will make.

 

Again...What is a BTU? A BTU is the equivalent of 252 heat calories, don't confuse that with food calories or kilo-calories of food. One BTU is approximately a third of a watt of electrical power or 1 horsepower is approximately 2540 BTU/h. Now most pump gas either premium or regular, have roughly the same heat content (about 124,800 Btu) per gallon (U.S.). Gasoline blends containing ethanol will have a slightly lower heat value. The colder the cumbustion chamber the less BTU's it produces even with the same amount of fuel. So you then heat the combustion chamber to it's maximum without melting the internals and move that energy down the exhaust pipe to the turbine which is moving with the kenetic energy the motor is producing. The colder the exhaust temp the less boost you produce because the physics and all those fancy words and terms like Kenetic Energy, mass, local acceleration of gravity (also part of the mass equation), and dimension constants come into play. If you do not pruduce BTU's you do not produce the Kenetic Energy and flow of gases required to turn the turbine wheel which needs alot of energy to compress air enough to make one pound of boost...let alone 12, or 20, or 30 PSIG. Why do you think it takes a 500HP gasoline engine to turn a compressor wheel that produces 40-50PSIG of boost to then make that engine produce 1000HP when it is at full boost? Crude example I know...but gets the point across.

 

Why do you think the VHT turbo's used on Dodges spool so fast yet have the ability to produce boost at high RPMs? Because they change the "demension constants" to allow for the compressor to gradually build boost while allowing the turbine wheel to spin at maximum speed during the transition. They didn't change the mass of the compressor wheel...just it's demension constant to minimize the load on the wheel.

 

You can find the BTU rating for gasoline on Gale Banks' webpage. I think he knows a thing or two about turbos. You can find the definition of BTU and how it is a factor with energy production here http://en.wikipedia.org/wiki/BTU

 

Now as far as producing boost in Park/Neutral in an LG5 or any other turbo'd car without a two step. YES YOU DO! Do you produce 5 pounds or more without computer/timing assistance...NO! At least I hope not! If you are then you have some serious friction problems! You require a load to produce boost otherwise you freewheel the turbo and just flow air through the compressor wheel. Now...with that said. How much load do you produce just to spin an internal combustion engine's crank, piston's, valve train, oil pump, etc? 50 HP...another 5-10 HP for an alternator under load...another 5 or 6 HP for your water pump...another 4-6 HP for your power steering? That is a LOAD! Not the same load as accelerating your car down the road to get that FULL boost...but it will cause enough of a load to get a pound or two out of your turbo. I just looked at one of my datalogs from my car. My MAPvariable at key on was 2.12VDC. That means that no vacuum/no boost the MAP sensor read atmospheric pressure or what you feel on your skin right now. Just blipping the throttle threw the MAP to 2.67 and 2.52VDC. Now this MAP sensor is a 0-5VDC. Do the math and you will see that just blipping the throttle to 4000RPM produced BOOST! How much? Sorry I do not have my Slide-Rule in front of me to give you an exact number...but it is boost. 10 lbs...Not even close but it answers your original question!

why dont turboed cars make boost when they are not under load!??!

 

They in fact DO!

 

Now this is what makes me laugh and I don't want to sound like a prick to you because you are still learning as am I. But by the sounds of it you have read one book and you are jumping down my throat like you are some expert on N/A or turbo'd cars. Sorry man but you have a long way to go. I have been around turbo's for damn near 20 years and I learn something new everyday that I am around them! For right now you may want to take a seat and do some more research before you jump.

 

Ok...I am off to bed after writting a Jeff M novel (just playing Mr. M! )!

 

Peace gents...Kenny

 

*edit* after re-reading the post I made I realized I mispelled COMBUSTION everywhere...oh well I am tired and consider this the full edit!

 

 

[GutlessSupreme]

lol

 

x2.

[Jeff M]

Ok...the problem is you are not looking at what happens before the turbo and this is what I was trying to spark with your thinking. Obviously this back-fired and you went on a tangent! No surprise there.

 

And that is all I seen it as too, to only offer that there is more to think about, and that no one book has all the answers, and as Kenny admits as do I, but no one else I guess , that no one man including all of us has all the answers! That also means avoid making statements of absolution, not only can that lead to sticking your foot in your mouth later, but you set yourself up begging for someone to put you down, not the best way to learn with this negative type of an approach tactic, but this will also start a war that most Mods don't like having to deal with .

 

Hey futuretgp'r, you checking your emails once in a while there is an update for you and some questions that need to be considered, and answered

 

Jeff M

[joberlee]

i'll second that, if you stop considering new possibilities and just accept what's there nothing ever changes.

 

remember, several hundred years ago all of the smartest people on the planet thought it was flat. It was considered fact, there were books written all about it. So one book on a topic may not cover all aspects of the topic.

[futuretgper]

finally i got out of you what you should have said the first time TGPilot!!! damn it took some work though!!! i still don't see why you had to explain, in detail, what a BTU was when we were talking whether or not a hotter or cooler gas helped produce boost, i know what a BTU is and in the context (all other things equal, ex: intake temp, cylinder temp, exhuast temp, everything pre turbo accept for distance to the turbo) i theres no need to know what that is. the principle of which we speak is a broad one which you summed up: MORE HEAT = MORE ENERGY, which i happened to state about a million times.....from what you wrote you do agree with me! and you asnwered my question (my best bud now!! ! i never came close to making any abosolute statements on my original question!! i merely asked it and allowed anyone to give me an answer....you also make a very good point about the load cuased just by sping the interal and acsessories, that was some good out-side the box (my box at least) thinking! i know i sound like im an "expert" and a prick but its only to provoke what i evently got......a straight answer!!!

 

thank you and i appologize for being a dick...but i love to get into it and really hammer stuff out...we are all big boys and some strong talk shouldn't scare anyone away!! my promise is that ill never be closed minded to reason, just show your reason/logic and ill bow down....i love getting into things like this and i get worked up so please try not to take anything personaly!!

 

p.s. if you can blip the throttle up and make boost...can you sustain boost or is the load of accelerating the internals, accessories, ect...the only way to make boost.......what im getting at is once you spin up the engine and hold it at a stable rpm, much of the load on the engine is not there anymore due to the fact that you are no longer accelerating mass. so do you loose boost right away or does it just fall off a little or not change at all! i realize that the setup of each vehicle (mass of internals, lack of accessories being driven, ect...)will change these factors but let me just ask for this: what happens in the TGPs....if it cant sustain boost then i wouldn't really consider it to be able to boost in neurtal.....well it could obveously! but not in a practical appliable manner ie. launching a manual TGP under boost! if what i suspect is right it would be at best difficult to time and launch under boost in a manual TGP!

 

[joberlee]

when you let off the gas the turbo does not immediately slow way down. It is still able to produce boost for a short period of time as the engine slows down. This is why you're supposed to let the car idle after driving it before you shut it down. The turbo takes a fairly long time (up to 30 seconds or so) to come down to it's idle with the engine at idle.

 

What you need to have to make boost is very simple. The turbo must be spinning VERY FAST. You don't want to launch the car while it is under boost as you will get no traction. What you do want is the car to come on to boost as quickly as possible. So if you blip the throttle repeatedly as you are getting ready to launch and get the turbo spooled up a bit when you launch it should boost faster than if you had just let it idle. Keep in mind that the turbo has a good amount of mass to it in the turbine, compressor wheel and shaft. It's this mass that you need to get moving ahead of time.

[futuretgper]

i don't think its making any boost in the manifold if the throttle body is closed which it would be if you only bliped it....then when you let off if you don't have a BOV your gonna bounce the air between the turbo and throttle plate cuasing the turbo to slow down pretty fast!

 

You don't want to launch the car while it is under boost as you will get no traction

 

thats a pretty bold statement!! stutter boxes (2 step for TGPilot), brake boosting meant to leave the line under boost! im sure there are good reasons to leave under boost!

im sure sleepered90 wants to/does hes running slicks and mid 13's

[joberlee]

the idea is not to have the intake already under boost, you'd have to just rev the fuck out of the engine to launch that way. What i'm talking about is getting the turbo spinning faster than it would normally be while you are idling. the faster it's already spinning (even if it is producing no boost) when you go to launch the car, the faster it will come up to boost.

 

with a 2 wheel drive car, unless you are running some pretty serious high dollar race setup, you don't want to be at full potential power when you launch. Because you will just burn the hell out of your tire instead of actually going anywhere. If you are running slicks, or awd, etc then yes, you can by all means have you car under full boost when you launch and hope you don't break anything[br]Posted on: April 13, 2006, 11:51:18 PM_________________________________________________

p.s. if you can blip the throttle up and make boost...can you sustain boost or is the load of accelerating the internals' date=' accessories, ect...the only way to make boost.......what im getting at is once you spin up the engine and hold it at a stable rpm, much of the load on the engine is not there anymore due to the fact that you are no longer accelerating mass. so do you loose boost right away or does it just fall off a little or not change at all! i realize that the setup of each vehicle (mass of internals, lack of accessories being driven, ect...)will change these factors but let me just ask for this: what happens in the TGPs....if it cant sustain boost then i wouldn't really consider it to be able to boost in neurtal.....well it could obveously! but not in a practical appliable manner ie. launching a [b']manual[/b] TGP under boost! if what i suspect is right it would be at best difficult to time and launch under boost in a manual TGP!

 

I just re-read this, you need to think of the turbo as a seperate item from the engine. The turbo does not instant respond to changes in engine rpm like a supercharger would. it takes time to come up to speed, and time to come back down from that speed.

 

Here's an intersting idea, staged turbos:

 

take one turbo with a small inlet and a fast spooling turbine, put a larger high volume compressor on the other side of it. now take the compressor output from this turbo, reduce the size of the pipe, and run that into the turbine side of a larger turbo, take the output from the compressor on this turbo and run it into your intake. the smaller first turbine would spin very fast at lower engine rpm, pushing a large amount of air into the second turbo from the compressor on the first turbo, allowing it to spool up to boost range while the engine was still basically at idle

 

Does anyone else think this might possibly work?

 

 

[futuretgper]

i think you misunderstood me......i never said anything about being at full power potential off the line........that would be like reving to full rpm and dropping the clutch....or putting the brake on and flooring the gas then let the brake out......im just talking about having some boost made.....

 

 

the idea is not to have the intake already under boost, you'd have to just rev the fuck out of the engine to launch that way

.

 

no you wouldn't have to, either you power brake (which i admit ive tried a few times) and it doesn't take much for RPMs to pressurize the intake....or in a manual car use a stutter box.

 

dont worry i understood your idea about getting the turbo spinning faster...its not that tough of a concept. i think it would work some but i also think if your reving and leting off your bouncing alot of air off the compressor and slowing it down between revs especialy without a BOV. and i think if you just slightly brake boosted (just barely) it would be a better route than what you describe.

 

also:

you need to think of the turbo as a seperate item from the engine. The turbo does not instant respond to changes in engine rpm like a supercharger would.

 

haha i know that the turbo doesn't respond in a linear fashion compared to engine speed (especialy from a launch or lower RPMs)...i already mentioned "lag" in one of my first posts....my recognition of this displays my awareness of the concept.

if you read TGPilot's last post his findings (hard data) show the turbo on the the TGP (small and responsive) does make a quick spike of boost if you blip the throttle! implying that it does respond quite quickly, but thats just our cars.

 

i think you sequential idea (which is basically the RX7 setup i described in an earlier post) is a long shot...too many things working against it to create boost at idle.

 

what more i don't get is which do you want no lag or lag?? first you imply that a lag free car is possible:

A friend of mine tried to argue that a turbo car would always have lag

and then you contemplate a setup that may make boost at idle.....sounds to me like you interested in decreasing lag!!

but:

you don't want to be at full potential power when you launch. Because you will just burn the hell out of your tire instead of actually going anywhere

so why the interest and which do you prefer?

[joberlee]

i'd love to have something like that on an awd car, old subaru wagon or something, so as soonas you hit the gas your in boost. probably not practical on a w-body, or most cars for that matter as it would be one big setup. i think that setup would be very interesting in how it would respond, you'd get the benifit of a small turbo off the line and a big turbo as high rpms, but with out the complication of it being a sequential setup.

[TGPilot]

If you are reading boost it is in the manifold...the MAP sensor piping inlet is after the throttle body. Will you SUSTAIN boost in P/N with an LG5...no because the load to spin everything up is gone once it is in motion. You want to build boost in P/N or clutch in on a 5-speed...get a two step.

 

As far as power braking the car to build boost...why not? I do it in the TSTE anytime some ricer or Mustang GT wants to play. It allows for a much better launch with more power. Now if you know how to drive a car you know how to feather the throttle to allow for maximum boost and maximum traction. Can most thin tired FWD cars hold 100% traction when 280ft/lbs of torque is trying to turn the tires? NO!...but if you roll the throttle you can get the car in motion with just the slightest squawk from the tires and then roll the rest of the way back in to pull the car. Now you should not sit there for more than 5 seconds power braking the car as the tranny will show you just how much it hates heat!

 

Building boost with a 5-speed TGP...my 60' times are comparable with most any NON SLICK car that has posted on here in the past. You have to remember about the design of our turbo and intake system. Plenty of bottom torque. At launch the N/A portion (before boost) has the same torque power ratio as a 3.1 liter...then it takes 1 second for my car to be at full boost. Well guess what...my car is in motion when it builds boost allowing for a nicer ramp to speed. Unless you have slicks and the track is prepped with VHT...you will spin NON-slicks off the line in a TGP/TSTE auto car. The tires I have on my car now on the street will not allow spin in 2nd....where the tires before would allow spin into 3rd. I am going to Bandimere this Saturday which is one of the best tracks in the country for prep. I have a feeling the tires on the car now will grab like slicks and not allow ANY tire spin off the line.

 

Can I build boost with my 5-speed off the line...SURE if I want to glaze my clutch again! Side stepping the brake and throttle is not difficult while slipping the clutch. You build boost that way because you are putting a load on the engine. Not good for a clutch at all...but it can be done.

 

Anyway...I am off to get some work done today.

 

 

 

 

[futuretgper]

tgpilot do you run a manual boost controller on the 5 speed? what kind of 60's do you run? what tires do you run on your cars (width brand)??

[TGPilot]

No I run the stock boost control solenoid. Makes it so if the timing gets crazy for knock then it will pull boost also. With a manual you have no auto control if things get ugly.

 

I put a set of Continental Extreme Contact on...they are gummy soft and wicked for traction...even in the rain or snow. 245/50/16

 

 

60' best was a 2.134 at Bandimere which scared me that the tranny would blow....average easy launch is normally 2.4xx at the same track. If I go to Pueblo they get worse...shitty track. Oh and those were with the old tires which did not grab very well. They were Good Year Eagle HP's 245/50/16. I will see what the Conti's do tomorrow.

[joberlee]

 

i think you sequential idea (which is basically the RX7 setup i described in an earlier post) is a long shot...too many things working against it to create boost at idle.

 

what more i don't get is which do you want no lag or lag?? first you imply that a lag free car is possible:

A friend of mine tried to argue that a turbo car would always have lag

and then you contemplate a setup that may make boost at idle.....sounds to me like you interested in decreasing lag!!

but:

you don't want to be at full potential power when you launch. Because you will just burn the hell out of your tire instead of actually going anywhere

so why the interest and which do you prefer?

 

Both, you can always turn down the boost by way of an rpm trigger, gear trigger or even a speed trigger. I know that ford/ mazda did this in the probe turbo cars. they had a gear selsction sensor so that it would only boost after you were above a certain rpm when in first gear to make the car more driveable. Just because the boost would always be there doesn't mean you'd have to be using it all the time. What i kind of have in mind is a to use a boost venting (not quite a bov but similar idea) system to control the actual amount of boost going to the intake. So the charge hose would have boost all the time, but the the intake pressure would be controlled by venting pressure after the turbo. If you can keep it spooled continuously it will have instant boost whenever you call for it.

 

Lag is not only an issue when launching a car. If you ever drive something like an old sunbird turbo or the old riviera i had you will know exactly what i'm speaking of. You are running 45 mph in third gear (3 speed auto) and you suddenly need/ want to accerlate very quickly. You slam down the pedal, and you wait, and you wait and then all of a sudden it slams you back in your seat. lag at speed is not an issue in the tgps due to some decent engineering and a relatively short intake path.

 

So the basic idea i've always had is that you can always turn away boost that you don't need, but it's damn hard to make it appear instantly when you do need it. So why not let it be there waiting for you to call on it all the time?

 

Oh.. and the turbo setup i was talking about is just a concept in my head at the moment, but it would definently need an oil supply reservoir. It would never spool down when the engine was running, so you'd run it out of oil and burn up the bearings or at least the seals if you shut it off and didn't keep oil flowing to it for a while.