Dyno Numbers are In!
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Joined: May 2003
Posts: 6,661
From: LA (lower Alabama)
Re: Dyno Numbers are In!
Originally Posted by Deenasty
The heads flow 275/198 @ .600 (Do you need all the numbers?) Unfortunately, the manifold is bare, never had any porting. I know that my heads are lt1 style and the manifold is an lt4 style, but from what I know, the port on the lt4 manifold in actuallity is a bit "smaller" should we say, do to its shape. I have been thinking about pulling it off and having it ported, or perhaps putting a stock lt1 manifold on it. I thought that the 52mm tb would be sufficient, but perhaps I could be wrong. I know that dyno numbers arent everything, and in actuallity its how the car runs. I really dont mind the rwhp numbers, as long as the car can run in the mid to high 11's. I dont know if it is possible with this setup, I hope. I have a feeling that my injectors, nor is it fuel related, because the AF stayed consistent. I really dont know what to do as from this step forward. I had heard many good things about the ZZX cam, from very respected people, such as mindgame as well. Im not sure if the camshaft is giving all its got, or if there is something wrong with the setup..Thanks Guys!
With 30lber's you can make 425FWHP@6800rpm's @43psi fuel pressure at 88.5% duty cycle with 15.63ms pulse width @.5 BSFC. If you want to make more with the 30's you will have to increase the fuel pressure.
The intake being a tad smaller than the heads isn't correct but it is not a killer either. Better that way than the other. I would look somewhere else for the problem, like maybe fuel related.
You are making about 435FWHP now so it adds up
(maybe)
Last edited by 1racerdude; Feb 10, 2005 at 03:51 AM.
Registered User
Joined: Dec 2000
Posts: 766
From: GARDNERS,PA
Re: Dyno Numbers are In!
You may also do a run with no CAI and Air Filter, I found that my Moroso CAI was holding me back by 10 RWHP with back to back duno runs. The little Air filter on the Moroso setup is probably the culprit on my setup. I'm currently fabbing a 4" CAI with a big honking K&N down in the fender. I am also going to run thru a pair of bullets then a pair of cut outs before the Y transition. This will allow me to have a very quiet ride on the street, yet a free flowing exhaust for the track.
Your torque looks nice and flat
Steve
Your torque looks nice and flat
Steve
Registered User
Joined: Apr 2004
Posts: 274
From: Denver
Re: Dyno Numbers are In!
Originally Posted by Deenasty
I know that my heads are lt1 style and the manifold is an lt4 style, but from what I know, the port on the lt4 manifold in actuallity is a bit "smaller" should we say, do to its shape.
Was work done to match these two?
11" vacuum
, that is what I might expect to see at altitude with that cam. Doesn't seem right, ?????
Registered User
Joined: Jul 2002
Posts: 1,193
From: San Diego, CA
Re: Dyno Numbers are In!
Originally Posted by Deenasty
no work was done to match the head to the intake, unfortunately....
so do you guys think it can be injector related?
so do you guys think it can be injector related?
I never meant to infer that it was injector or fuel realted. You said the A/F was fine throughout the run...so your injectors and pump are fine. I only meant that if you start spinning higher, you will find out if they are up to par.
The best and cheapest way to check, is to check the duty cycle. Download a program called Data Master from www.AKMcables.com. This program once installed allows you 20 free scans before you have to purchase the program. Use one of the scans and check what your duty cycle is. If it is high in the upper RPMs then you might need to adjust the fuel pressure/upgrade injectors or pump.
Do the cheap stuff first...like spinning to 6600 or something. Then check your vacume and see if you have any leaks or restrictions. If so, try freeing up the intake and exhaust (cutouts/no filter etc).
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Joined: Mar 1999
Posts: 2,067
From: Kernersville, NC
Re: Dyno Numbers are In!
Originally Posted by LT4383
Correct me if I'm wrong, but I didn't think they matched up. ??
Thread Starter
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Joined: Jan 2004
Posts: 1,322
From: San Francisco
Re: Dyno Numbers are In!
i will try the inexpensive stuff first. As for the lt4 manifold not matching up right to the lt1 style head, that is correct. But, the only thing that could be happening due to this mix up of styles, is that the setup is being "choked" by the manifold, because the ports on the lt4 manifold are "smaller" sort of say. They just have more material on them, in order to allow for porting.
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Joined: Apr 2004
Posts: 274
From: Denver
Re: Dyno Numbers are In!
Last I checked they don't match up well at all!! I would think that is the majority of the problem. I think I would use an LT1 intake with LT1 heads and LT4 I w/ LT4 H. Good luck.
Thread Starter
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Joined: Jan 2004
Posts: 1,322
From: San Francisco
Re: Dyno Numbers are In!
Originally Posted by LT4383
Last I checked they don't match up well at all!! I would think that is the majority of the problem. I think I would use an LT1 intake with LT1 heads and LT4 I w/ LT4 H. Good luck.
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Joined: Oct 2002
Posts: 66
Re: Dyno Numbers are In!
You shouldnt have a problem at all with running mid to high 11's with this setup. I had a 0-deck 355, stock crank and rods, .030 rebuild kit with 4 valve relief flat top hyperutectic pistons, with p/p stock castings, didnt touch the intake, 52 mm tb, 30# injectors, converter, auto trans and 26/10/15 et drags. The car went 11.80's all day long. (tuned with lt1-edit) The car had a 1.61 60' with stock rearend with the stock 3.23 gears. 7.90 1/8 mile times. This is to say u get right tune in the car and definately spin it higher with that cam. I had a 224/230 114 lsa 503/510 Comp in my car. Turned it 6300 rpm's. Good luck man!!!
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