Need help low 230/236 AI heads dyno results.
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Joined: Jan 2003
Posts: 1,362
Re: Need help low 230/236 AI heads dyno results.
Air filter? Could be something as stupid as that. Also your MAF could possibly be reading wrong. Try borrowing Turbo Z's. Check for vacuum leaks as well, those will kill the top end.
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Joined: Nov 2001
Posts: 3,515
From: Kansas
Re: Need help low 230/236 AI heads dyno results.
Originally Posted by Pasky
Air filter? Could be something as stupid as that. Also your MAF could possibly be reading wrong. Try borrowing Turbo Z's. Check for vacuum leaks as well, those will kill the top end.
I was there when the cam went in and can varify its not off a tooth. So pretty much we are looking at a bad cam or some kind of restriction which IMO really isnt bad looking at the datalog. Something else odd is that my original logs on the dyno before the heads look about like z95m6s.. same air flow and same amount of fuel. Power is just considerably less. So im thinking intake valve opens too late and exhaust valve opens too late if thats even possible....
Thread Starter
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Joined: Oct 2001
Posts: 6,070
From: newton, kansas, USA
Re: Need help low 230/236 AI heads dyno results.
Originally Posted by tireburnin
I'll add my couple of ideas.
Cheap and easy:
Your website lists a borla (w/ electric cutout) and midlenths as your exhaust. That is crappy for performance right there. What are you using for a Y pipe? A fairly cheap mod that should help some...a cutout closer to the merge of the y pipe. I picked up 30rwhp+ from cutouts near the header. The overall setup isn't very condusive to hp, but it would be expensive to replace/upgrade.
If you have comp Rs at 1/4 past they are too tight. Mine are at 1/8 to 1/4 and were too tight. My car stopped pulling at 5700 when it shouldn't have. I'm going to go to 0 lash (maybe just a hair past to keep them a little quite). Lash can have a big effect on powerband and upper RPM stuff. Loosen those up a bit.
Have you double checked your TB is operating correctly? Mine was a PAIN to get even somewhat liveable. It wasn't opening fully and sometimes stuck open. Check that its opening 100% and that the TPS sees it as 100%. (Simple and common sense but easily overlooked).
Sorry to hear your still having problems...once you get it running correctly it will be a beast. Don't give up on it.
Cheap and easy:
Your website lists a borla (w/ electric cutout) and midlenths as your exhaust. That is crappy for performance right there. What are you using for a Y pipe? A fairly cheap mod that should help some...a cutout closer to the merge of the y pipe. I picked up 30rwhp+ from cutouts near the header. The overall setup isn't very condusive to hp, but it would be expensive to replace/upgrade.
If you have comp Rs at 1/4 past they are too tight. Mine are at 1/8 to 1/4 and were too tight. My car stopped pulling at 5700 when it shouldn't have. I'm going to go to 0 lash (maybe just a hair past to keep them a little quite). Lash can have a big effect on powerband and upper RPM stuff. Loosen those up a bit.
Have you double checked your TB is operating correctly? Mine was a PAIN to get even somewhat liveable. It wasn't opening fully and sometimes stuck open. Check that its opening 100% and that the TPS sees it as 100%. (Simple and common sense but easily overlooked).
Sorry to hear your still having problems...once you get it running correctly it will be a beast. Don't give up on it.
Retired
Joined: Oct 1999
Posts: 3,166
From: Inside Uranus
Re: Need help low 230/236 AI heads dyno results.
Originally Posted by Z95m6
The exhaust may not be the best setup but i know it isn't costing me 75+rwhp. I'm running Comp R's. I know it sounds crazy but with the Comp R's in there the car doesn't seem to lope as much so maybe they are too tight now. The TB is opening all the way and i'm running a 58mm tb so it can't be an intake restriction anymore. I'm at college right now so i'm leaning towards checking the lash, compression and fuel pressure. I'm pretty sure the last 2 aren't the problem but then its at least ruled them out. I don't think the MAF is the problem either for the reasons Rich pointed out.
Vaccuum leak? Compression test? Something is definetly fishy if the MAF is only pulling 280 gm/sec of air. My 396 pulled around 400ish at WOT @ 6800 rpm.
Do you have a Scanmaster or other device to show real-time values? I bet you could figure out the problem if you saw exactly what was going on while it was going on.
Mike
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From: newton, kansas, USA
Re: Need help low 230/236 AI heads dyno results.
Originally Posted by Kraest
The exhaust should be fine, since you have a Borla (plate wide-open?) and a cutout (basically the same thing). The headers aren't going to cause that much chaos.
Vaccuum leak? Compression test? Something is definetly fishy if the MAF is only pulling 280 gm/sec of air. My 396 pulled around 400ish at WOT @ 6800 rpm.
Do you have a Scanmaster or other device to show real-time values? I bet you could figure out the problem if you saw exactly what was going on while it was going on.
Mike
Vaccuum leak? Compression test? Something is definetly fishy if the MAF is only pulling 280 gm/sec of air. My 396 pulled around 400ish at WOT @ 6800 rpm.
Do you have a Scanmaster or other device to show real-time values? I bet you could figure out the problem if you saw exactly what was going on while it was going on.
Mike
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Joined: Jul 2002
Posts: 1,193
From: San Diego, CA
Re: Need help low 230/236 AI heads dyno results.
Yeah, I didn't mean to infer that the exhaust was costing you 75rw, but it would be worth 10-15rw. And other than the lash, I was just throwing out things to check.
If you can't track it down and all of your sensors/reading check out...try swaping cams. Maybe a GM847 or something. It isn't far fetched to have a cam ground wrong. It is more common with custom grinds, but who knows. You sure the cam is a 230?
Are all the cylinders firing (primaries hot and such)? Maybe a dead cylinder?
If you can't track it down and all of your sensors/reading check out...try swaping cams. Maybe a GM847 or something. It isn't far fetched to have a cam ground wrong. It is more common with custom grinds, but who knows. You sure the cam is a 230?
Are all the cylinders firing (primaries hot and such)? Maybe a dead cylinder?
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Joined: Dec 2004
Posts: 484
From: Orlando FL
Re: Need help low 230/236 AI heads dyno results.
Originally Posted by tireburnin
Are all the cylinders firing (primaries hot and such)? Maybe a dead cylinder?
. And if it works then just keep that one in there. As long as your springs can handle the .598 lift with 1.6's.
Thread Starter
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Joined: Oct 2001
Posts: 6,070
From: newton, kansas, USA
Re: Need help low 230/236 AI heads dyno results.
Originally Posted by tireburnin
Yeah, I didn't mean to infer that the exhaust was costing you 75rw, but it would be worth 10-15rw. And other than the lash, I was just throwing out things to check.
If you can't track it down and all of your sensors/reading check out...try swaping cams. Maybe a GM847 or something. It isn't far fetched to have a cam ground wrong. It is more common with custom grinds, but who knows. You sure the cam is a 230?
Are all the cylinders firing (primaries hot and such)? Maybe a dead cylinder?
If you can't track it down and all of your sensors/reading check out...try swaping cams. Maybe a GM847 or something. It isn't far fetched to have a cam ground wrong. It is more common with custom grinds, but who knows. You sure the cam is a 230?
Are all the cylinders firing (primaries hot and such)? Maybe a dead cylinder?
Thread Starter
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Joined: Oct 2001
Posts: 6,070
From: newton, kansas, USA
Re: Need help low 230/236 AI heads dyno results.
Originally Posted by Kraest
Vaccuum leak? Compression test? Something is definetly fishy if the MAF is only pulling 280 gm/sec of air. My 396 pulled around 400ish at WOT @ 6800 rpm
Mike
Last edited by Z95m6; Mar 30, 2005 at 04:40 PM.
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Joined: Nov 2001
Posts: 3,515
From: Kansas
Re: Need help low 230/236 AI heads dyno results.
Originally Posted by Z95m6
Are you saying i should look into a vaccuum leak or compression test? or are you saying those can't be the problem. Thanks Claude.
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Joined: Apr 1999
Posts: 753
From: Chandler AZ
Re: Need help low 230/236 AI heads dyno results.
to be down as much power as you are it probably is a combination of things but if your car is starting hard there is a reason. I believe you said you were gettng knock retard too.
If your car isn't using oil then I doubt you have a compression problem.
I think you have a cam/ valvetrain problem and tune.
Since you have knock and your car is not reving to where it should I would start with re-adjusting your rockers and a fuel pressure test.
If fuel is ok and the rocker adjustment doesn't help you've got to degree the cam. Also isn't there a model number or something stamped on the end that you could verify?
We had a guy in AZ who was off one tooth on the cam install and he lost over 50rwhp. In know you say this was verified but the cam could be ground wrong or it could be the wrong cam.
If your car isn't using oil then I doubt you have a compression problem.
I think you have a cam/ valvetrain problem and tune.
Since you have knock and your car is not reving to where it should I would start with re-adjusting your rockers and a fuel pressure test.
If fuel is ok and the rocker adjustment doesn't help you've got to degree the cam. Also isn't there a model number or something stamped on the end that you could verify?
We had a guy in AZ who was off one tooth on the cam install and he lost over 50rwhp. In know you say this was verified but the cam could be ground wrong or it could be the wrong cam.
Thread Starter
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From: newton, kansas, USA
Re: Need help low 230/236 AI heads dyno results.
Originally Posted by SStrokerAce
I would do a compression test and degree in the cam, make sure the mechanical things are right first.... then look at fuel and spark, those are the next too things.
Bret
Bret
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Joined: Nov 2001
Posts: 3,515
From: Kansas
Re: Need help low 230/236 AI heads dyno results.
Originally Posted by SStrokerAce
I would do a compression test and degree in the cam, make sure the mechanical things are right first.... then look at fuel and spark, those are the next too things.
Bret
Bret
Heres a run down of what I have. comp cam, comp pushrods(OEM length), comp 987 springs, comp NSA pro mags and stock lifters.