Mark VIII motor
cobra crank
manley rods
diamond 9cc dish pistons
03 cobra cams
98 cobra intake
03 cobra exhaust manifolds
Procharger D1SC 3.4 inch pulley
SLP catted X pipe
Tuning by Dave at SGS
Initial tune with nasty plastic procharger blower inlet pipe and small air filter plus stock ford catback. 489 hp/439 tq 17-18 psi boost Air filter was flattened. 23 degrees of timing
Changed to homemade 4 inch powerpipe and Pypes race pro catback. This time first pull was cut off at ~6000 rpm making 537 hp and climbing. Boost heading towards 20 psi. Dangerous situation with 93 octane. Cut the timing back to 20 degrees and got spark blow out. Gapped the plugs down from 0.032 to 0.024.
Final numbers 527 hp/463 tq with a nice safe tune for pump gas. 20 psi boost at 7000 rpm. Gains over the previous tune increase thru the entire powerband. Unfortunately raining the whole day and weekend, did not get to have much fun with it.
So as it turns out, it was good to get it tuned again. I had thought I heard some detonation after the powerpipe when running hard in 3rd and 4th (always let off at the first sign).
Erich
Erich, that graph looks great! i have a few questions since i plan on stepping up to a D1 pretty soon. Are you still running 6 rib and if so any problems with belt slip? What does your fuel system consist of?
Thanks!
Yep still running a 6 rib. I have an 8 groove ATI dampner on there just in case I need to go to 8 rib but it has been really good as far as belt slip/breakage. The D1 has a much bigger pulley on it than I had on my old P600B. I think that helps with the slip and belt life stuff.
For a fuel system I have an intank walbro 255 and an external bosch 044. I just adapted the bosch to work with the stock lines. Injectors are 60#, Maf is PMAS with a 24/60# calibration. I really like that bosch, it is way quieter than my old procharger external pump plus it can deliver 300 lph at high backpressure.
Only thing missing right now is a better bypass. Getting lots of compressor surge from the supplied procharger one. Will likely go with the minirace one from vortech.
Erich
Thanks! Looks like you have an awesome car there-handling and power!
How do you like the mondo bypass? I want to get a bypass that I can direct the air somewhere to quiet it but still make sure there is no surge.
The stock procharger bypass is right next to the blower outlet. The guy who tuned the car said that was a bad location. Better was to move the bypass to right before the IC so the air gets smoothed out before the MAF.
Erich
thanks bud. well typicall you have a blow thru not a draw thru it sounds like ur draw thru right now. so what u'll want to do is put the maf on after the blower and the bypass before that.. i like the mondo all in all though. my big question is why are you only making 5xx on 20lbs!! you should be in the 650rwhp range with that boost.
Last edited by 98 Saleen Cobra; 10-21-2009 at 01:44 PM.
Yeah, I have a blow thru setup.
I also thought the power was low for that much boost. Here are a few more details-anything you can spot?
Only 20 degrees of total timing at the top. The first run at 23 degrees of timing was at 540 at about 6000 rpm and going up pretty sharply. Then with the amount of boost it was going to be making (on 93 octane) he stopped the run and backed off on the timing.
I don't have a good feel for if that is a normal amount of timing etc. Would I make more power with less boost and more timing?
The cams are 03 cobra which are supposed to be the same as the mach 1/marauder and maybe even mark VIII. So less aggressive there but 03 cobras make a ton of power with a pulley swap. I am assuming my cams were timed in correctly.
Running thru 03 cobra exhaust manifolds-I doubt this explains it but they are no long tubes. Could my cats be messed up? No codes anyway.
The heads had some work done on them and flow better than original.
Not sure what else. It is a pretty much stockish built 4V with alot of boost.
Erich
thanks bud. well typicall you have a blow thru not a draw thru it sounds like ur draw thru right now. so what u'll want to do is put the maf on after the blower and the bypass before that.. i like the mondo all in all though. my big question is why are you only making 5xx on 20lbs!! you should be in the 650rwhp range with that boost.
Just my observasion, low compression, early B heads from mark 8(not as good as 96-98 Cobra B heads), 03 Cobra cams in early B heads(20 degrees less duration that 96-98 Cobra cams) and stock exaust manifolds.
Yeah, I have a blow thru setup.
I also thought the power was low for that much boost. Here are a few more details-anything you can spot?
Only 20 degrees of total timing at the top. The first run at 23 degrees of timing was at 540 at about 6000 rpm and going up pretty sharply. Then with the amount of boost it was going to be making (on 93 octane) he stopped the run and backed off on the timing.
I don't have a good feel for if that is a normal amount of timing etc. Would I make more power with less boost and more timing?
The cams are 03 cobra which are supposed to be the same as the mach 1/marauder and maybe even mark VIII. So less aggressive there but 03 cobras make a ton of power with a pulley swap. I am assuming my cams were timed in correctly.
Running thru 03 cobra exhaust manifolds-I doubt this explains it but they are no long tubes. Could my cats be messed up? No codes anyway.
The heads had some work done on them and flow better than original.
Not sure what else. It is a pretty much stockish built 4V with alot of boost.
Erich
Well everything looks good, I would obviously ditch the stock logs and go with LT's with atleast a 1-3/4'' primaries. Then a catless midpipe and a 3'' exhaust. what's your compression at?
Quote:
Originally Posted by 97desertCobra
Just my observasion, low compression, early B heads from mark 8(not as good as 96-98 Cobra B heads), 03 Cobra cams in early B heads(20 degrees less duration that 96-98 Cobra cams) and stock exaust manifolds.
Yea that's a good point right there, but still. I'm on a T-trim with a aftercooler not even intercooled and at 15psi i'm at 550rwhp and 477rwtq, and like 16-17* of timing. I have 04 heads and cams... hmm. interesting..
Compression ratio is about 9.5:1
Here are a few shots of the heads before and after work. Do you see any differences in the area around the valves? It looks like a different shape now but maybe it is an illusion.
Erich
Well everything looks good, I would obviously ditch the stock logs and go with LT's with atleast a 1-3/4'' primaries. Then a catless midpipe and a 3'' exhaust. what's your compression at?
Yea that's a good point right there, but still. I'm on a T-trim with a aftercooler not even intercooled and at 15psi i'm at 550rwhp and 477rwtq, and like 16-17* of timing. I have 04 heads and cams... hmm. interesting..
03/04 heads and 99/01 or mach intake is gonna net you a nice chunk of hp over a stock bhead setup, especially when you reach the upper rpm limit. Using the 03/04 cams vs the bhead cams will bring that back down 10-15hp.
20lbs of boost does seem like a lot with the 3.4" pulley, but boost is really just a measure of pressure in the engine (better flow will net you less PSI.) I bet with better heads, and at least a catless midpipe, the boost would drop a couple pounds, maybe around 15-16lbs and net some horsepower on the big half of the curve.
I think your biggest attributing factor is the factory exhaust manifolds along with the B heads and 03 cams. That 20 degrees less duration could be worth 10-15hp n/a, but that # climbs when you add boost. Plus the early B heads from the Mark 8 are a tad different than the ones on 96-98 Cobras. They dont flow quite as well and the B heads need the most help on the exhaust side. Even when ported the B heads have trouble matching stock C heads on the exhaust side. So pair that with stock headers and you have a big flow restriction. At this point headers may net you a big chunk of hp and with them your boost may drop a little, allowing you to pulley back up to 20 psi.
Yep, Dave did the tuning on both my cars. Great job. I trust his opinion and work and that means alot. He did tell me I should have gotten the 96-98 cams. He may not know about the exhaust. He told me to get a vortech minirace bypass to clear up my compressor surge. Did it and now it is gone and the lowspeed drivablility is improved for sure.
It would be interesting to change out just the exhaust manifolds and see what happens. I was shocked that the 03/04 outlets are smaller than my old 97 GT outlets! I had to make an adapter for my X pipe. Maybe I should have gotten even some cheap long tubes....Ah well, the car is running nice even though it is not hitting its potential. I drive it on the street everyday and it is a blast.
Erich
Just add water meth and get it tuned more aggressively. That will be your cheapest way out and u won't have to worry about detenation. I make 627hp through stock exuast manifolds, if u can get to around 560hp with 20lbs and meth with this setup u should be happy. Oh yea, get rid of those cats.
Just add water meth and get it tuned more aggressively. That will be your cheapest way out and u won't have to worry about detenation. I make 627hp through stock exuast manifolds, if u can get to around 560hp with 20lbs and meth with this setup u should be happy. Oh yea, get rid of those cats.
He should see great gains by removing the restriction, the exhaust. Its choking up his engine. Running more aggressive timing is not the answer if you have flow restictions. Those hot gases need to get out and in a hurry. His boost will probably drop but that will allow him to pulley back up to 20lbs. Meth is cool for some people. But after seeing a set of cylinder heads that where grossly corroded from using meth injection over an extended period of time I changed my mind on meth injection. I'm a believer in 2 tunes, race tune with race gas, more psi, and bumped timing and a street tune on pump gas with less boost and timing. E-85 is a good option for a race tune if its available in your area.
20 psi? WOW! I run the same size pulley on my D1-SC and with ported heads, cams, oversized valves and long tubes I only make 11.5 psi @ 6800 rpm LOL
Your ported heads flow more CFM than his do, plus you have long tubes and maybe you are running an o/r mid pipe. All of which would decrease the boost. You have to understand, its the CFM that is important from not only the intake side but the exhaust side when it comes to making power. Its about moving air not necessarily the amount of "boost" you are pushing.
Your ported heads flow more CFM than his do, plus you have long tubes and maybe you are running an o/r mid pipe. All of which would decrease the boost. You have to understand, its the CFM that is important from not only the intake side but the exhaust side when it comes to making power. Its about moving air not necessarily the amount of "boost" you are pushing.
I understand all that; I know 'boost' is just a measurement of restrictions but, I was just surprised by the dramatic difference in pressure. I am running a catted H-pipe not off-road and it's a difference of 8 psi on the boost-o-meter! haha
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