TurboZ24 Posted November 5, 2004 Report Share Posted November 5, 2004 Well, went too the track weekend before last, got a new best time of 12.3@114. The car didn't do as well as I hoped, but I did manage too get a datalog of the run. After looking at the log, it had horrible lag as well as pretty high intake temps. I mean like 4400 rpm it had like 4 psi, most of the time it didn't hit 12-13 psi until over 5500-6000 rpm. On the intake temps, it would start at a heat soaked 110, and then rise too 160 in the 12.3 seconds. So, started looking into the issue, finally pulled the turbo, checked clearances, took it back too the turbo shop and before we started resizing (not that it costs me a lot if anything....), the guy who rebuilds my turbo's suggested that I check everything once again, wastegate, etc. Went home, checked it all out. Capped the turbo, charged up the intake system with the air compressor set at 25 psi, found a few minor intake leaks. Then for some reason, I decided too look at the boost gauge and too my suprise it only read 10 psi..... So, decided what the hell and raise the air compressor too 45 psi, went too the garage, heard a hiss, and checked the gauge. Still read 10 psi....... Well, turns out the BOV was opening on it's own around 5 psi, it was just hard too detect since the air compressor only puts out around 4-5 cfm. So, fixed the issue with the BOV and man, what a difference.. Even with the T4 .68 A/R P-trim Turbine and 60-1 compressor, full boost is now achieved at 3000-3500 (depending on the gear) and intake temps stay within 10-15 of ambient. The car is just sickening fast now, it's amazing what a little problem like a leaking BOV will do.... Got a few other things I want too do to the motor (all minor), then back too the track in Febuary. Curtis 91' Turbo Z24 http://www.turboz24.com Quote Link to comment Share on other sites More sharing options...
TurboGTU Posted November 5, 2004 Report Share Posted November 5, 2004 THats sick! Yea...I know on my MX-6 I had a leaky BOV..dam plastic crap.. . :shock: Gee..you would think a boost guage is soppose to be accurate..guess not. I was thinking a leaky EGR when you said your intake temps would creap up..but I didn't think you had the EGR. Too bad now you'll need a rollcage. Now give the imports hell Quote Link to comment Share on other sites More sharing options...
TurboZ24 Posted November 5, 2004 Author Report Share Posted November 5, 2004 Gee..you would think a boost guage is soppose to be accurate..guess not. Actually once I fixed the BOV leak, the boost gauge read within 5 or so psi of the regulator on the air compressor, either the regulator reads wrong or there are enough minor leaks (it leaks slightly from around the throttle shaft) too cause a slight drop. Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted November 5, 2004 Report Share Posted November 5, 2004 Great numbers Curtis. Humm only have 1.7 seconds to go. Don't think our lead sleds will ever see thoes kind of numbers. Is your track closed for the winter? I hope Houston stays open at least till next Wensday. Jud Quote Link to comment Share on other sites More sharing options...
sl3196 Posted November 5, 2004 Report Share Posted November 5, 2004 Good work! Almost to the 11's! Quote Link to comment Share on other sites More sharing options...
TurboZ24 Posted November 5, 2004 Author Report Share Posted November 5, 2004 Is your track closed for the winter? I hope Houston stays open at least till next Wensday. Yeah, Ennis is closed, not because of weather, they close for the holiday season. Houston is open up until like the 19th of December I believe. Quote Link to comment Share on other sites More sharing options...
Jeff M Posted November 5, 2004 Report Share Posted November 5, 2004 Tooo good, SUPER JOB Curtis!!! Now we have more American FWDs running great numbers against the foreign competition!! 11’s should be easy now but you are going to have to use some other track that you don’t care to go back to . I can’t believe it was only a few weeks ago you had things apart, and were working on the new exhaust system in the engine bay :shock: . Really wish you had some exhaust backpressure readings, that I could compare to the turbos I have been testing, and other I will be testing!!! Sounds as though the little turbo lag you have is perfect for traction at launch, what was your 60-foot? If your rpms after shift are kept around 3,000 to 3,500 rpms then you will stay in your sweet spot/max boost, very nice 8) !! So what is your max boost for now, you didn’t say, 100 octane or 93? Yea a lot of questions, obviously you got me excited Again, congratulations!!! (yes, tech-chat next week, promise!!) Jeff M Quote Link to comment Share on other sites More sharing options...
TurboZ24 Posted November 5, 2004 Author Report Share Posted November 5, 2004 Well, Technically max boost on 93 octane is around 25 psi, that's what I intended a long time ago, but with all the changes too the motor I've made over time, I really don't have an idea anymore. It will probably boil down too where will the fuel system I currently have max out at. As for what I currently run, I have it set at 10 psi for now, it's still spooky fast at that. I did allow it too reach 16-17 psi, but got scared when I got rubber in 4th on the highway, so I don't think I'll let it go that high, at least for now on the street. I do actually plan on working on the lag too some extend, for street use it would be nice if it had a little less lag. I'm going too try a lightened turbine (that big ass lump is removed off the back of the turbine and it's balanced differently), so we will see what that will do. It's free too try out, so why not. I'd rather not swap too a .58 A/R, but if I can get a hold of a housing too try, might as well. As for future mods, I'm going too pull the pan, check the bearings like I usually do and put a windage tray in there. I'm swapping out the pressurized overflow and putting in the autometer gauges I have lying around, so a few things too do still. Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted November 5, 2004 Report Share Posted November 5, 2004 Yea Curtis Houston runs to the 19Th as you said but only on Friday and Sunday? No Wednesday night till next year. They open the 3rd of Jan. Just got of the phone with them. I guess you will have to come down here to race. Jud Quote Link to comment Share on other sites More sharing options...
TurboZ24 Posted November 5, 2004 Author Report Share Posted November 5, 2004 I guess you will have to come down here to race. I actually have thought about that, yes. Quote Link to comment Share on other sites More sharing options...
Jeff M Posted November 5, 2004 Report Share Posted November 5, 2004 Well, Technically max boost on 93 octane is around 25 psi, that's what I intended a long time ago, but with all the changes too the motor I've made over time, I really don't have an idea anymore. It will probably boil down too where will the fuel system I currently have max out at. As for what I currently run, I have it set at 10 psi for now, it's still spooky fast at that. I did allow it too reach 16-17 psi, but got scared when I got rubber in 4th on the highway, so I don't think I'll let it go that high, at least for now on the street. I do actually plan on working on the lag too some extend, for street use it would be nice if it had a little less lag. I'm going too try a lightened turbine (that big ass lump is removed off the back of the turbine and it's balanced differently), so we will see what that will do. It's free too try out, so why not. I'd rather not swap too a .58 A/R, but if I can get a hold of a housing too try, might as well. As for future mods, I'm going too pull the pan, check the bearings like I usually do and put a windage tray in there. I'm swapping out the pressurized overflow and putting in the autometer gauges I have lying around, so a few things too do still. Wow, 25 psi on 93 octane, what you running 6.5:1 compression ratio What is so nice about a wheel like in the 60-1 is at 10 to 12 psi the mass air/lbs-min are big and right in the highest efficiency range (around 78%, sweeeet) of the compressor wheel, but raise the boost further and you still got this sweet area running this wheel, so nice 8) !! As for turbo lag, still wondering if you got much lag after shift??....if you hit 10 to 12 psi at 3,000 to 3,500 rpms then would hope you have that after each shift, if boost is dropping too after shift then maybe blow-off valve needs some spring changes/tweaking. Last is to run a little leaner at lower boost levels in PE/Power Enrichment to get the boost up faster using the hotter and faster exhaust gases that running around 12.1 will give you, shooting for 11.9 the rest of the time to be safe. Depending on your combustion chamber might have to play with it and the timing some to keep things in safe limits. First need to check what A/F you have now, this might show why the boost is ramping where its at now. With your turbine housing, I would first check the backpressure before I spent the time swapping parts, this will tell you if there is a need mechanically yet. At 10 psi of boost bad is 25 to 35 psi or more of exhaust backpressure, better is 15 to 20 psi, best is 10 or less, even a few pros run less backpressure then boost but that takes some bucks and serious talent!! If you are running around 20 psi then don’t lower the turbine housing A/R, look to the above ideas, but if you got 10 psi of back pressure then yes a smaller A/R turbine housing is worth looking into but would still do the above. ALSO check the backpressure of the exhaust/at least 20 inches after the turbo, 2 to 4 psi is common, less is better, more could benefit from some efforts there. I have already told 6 guys today about your run, news is spreading fast!!!....hope you get another magazine article done, you deserve it with all the work you do, and or course the results :shock: . Jeff M Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted November 5, 2004 Report Share Posted November 5, 2004 but got scared when I got rubber in 4th on the highway, so I don't think I'll let it go that high, at least for now on the street. :shock: you're using the Getrag 282 right? do you have an LSD? what kind of 60' times are you getting with that? also this might sound stupid but are you launching in 1st or 2nd gear? mine feels sooooo steep in 1st...even with a 100hp NA 3.1 i can smoke 'em up with the 282 :? awesome times, good job Curtis Quote Link to comment Share on other sites More sharing options...
TurboZ24 Posted November 6, 2004 Author Report Share Posted November 6, 2004 Wow, 25 psi on 93 octane, what you running 6.5:1 compression ratio Well, a long time ago (feels like it at least), I did run the motor as high as 23 psi without any issues. Well, it didn't get any traction, but... Since then I have increased the head flow rates 59%, put in that excessive mechanical roller cam, etc, etc, so I have no idea if I could even get that high now. I guess I'll find out what it can do once I get it too the dyno for final tuning. you're using the Getrag 282 right? do you have an LSD? what kind of 60' times are you getting with that? Yes, I have a 282 (MG2, 5TM40, what ever you want too call it). I'm on my second one (kind of busted the first). I have a phantom grip in the car, but it doesn't really do much. The best traction improvement I saw was when I swapped too the older style intermediate shaft (the one with the housing and shaft inside). 60' times have never been lower than 1.802 Quote Link to comment Share on other sites More sharing options...
rudefyet Posted November 6, 2004 Report Share Posted November 6, 2004 so should we execpt your next run to be in the 11's? Quote Link to comment Share on other sites More sharing options...
TurboZ24 Posted November 6, 2004 Author Report Share Posted November 6, 2004 Hopefully I will see 11's, just have too wonder how many runs I can get in before they look for a cage that isn't there....... Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted November 6, 2004 Report Share Posted November 6, 2004 Congrats on the new PB Curtis...that's an awesome time despite the trouble you were having with the car. Good luck on hitting 11's! Oh yeah, if your track is like my local NHRA one, you might get in two runs tops before they either tell you to park it or leave. Quote Link to comment Share on other sites More sharing options...
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