Carburetor performance?
Drifting
Joined: Mar 2009
Posts: 1,253
Likes: 4
From: East Wenatchee (2hours from n e where) WA
To me the bottom line is;
Crossfire is cool because its Chevys first performance EFI and works pretty good in that light. But I dont see the Crossfire making more than 275 horse or making any meaningfull power over 5500 without a lot of work and money. The ECM can not manage enough valve timeing.
A 650, duel plane, pocket port 113s, cam and headers on the stock short block will make 75hp and 500+rpm more with a quick proven set up. I plan on retaining the ECM to control everything it does now, including WinALDL, except the fuel system.
Crossfire is cool because its Chevys first performance EFI and works pretty good in that light. But I dont see the Crossfire making more than 275 horse or making any meaningfull power over 5500 without a lot of work and money. The ECM can not manage enough valve timeing.
A 650, duel plane, pocket port 113s, cam and headers on the stock short block will make 75hp and 500+rpm more with a quick proven set up. I plan on retaining the ECM to control everything it does now, including WinALDL, except the fuel system.
Pro
Joined: Apr 2004
Posts: 621
Likes: 37
From: Texas
To me the bottom line is;
Crossfire is cool because its Chevys first performance EFI and works pretty good in that light. But I dont see the Crossfire making more than 275 horse or making any meaningfull power over 5500 without a lot of work and money. The ECM can not manage enough valve timeing.
A 650, duel plane, pocket port 113s, cam and headers on the stock short block will make 75hp and 500+rpm more with a quick proven set up. I plan on retaining the ECM to control everything it does now, including WinALDL, except the fuel system.
Crossfire is cool because its Chevys first performance EFI and works pretty good in that light. But I dont see the Crossfire making more than 275 horse or making any meaningfull power over 5500 without a lot of work and money. The ECM can not manage enough valve timeing.
A 650, duel plane, pocket port 113s, cam and headers on the stock short block will make 75hp and 500+rpm more with a quick proven set up. I plan on retaining the ECM to control everything it does now, including WinALDL, except the fuel system.
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
Figure 80-120 HP loss through the Manual trans or A4 auto, and the dana36 or dana 44 rear.
Nice power increase from stock.
Pro
Joined: Apr 2004
Posts: 621
Likes: 37
From: Texas
That motor was in a 79 Malibu with a turbo 350.
Maybe not quite as much loss but I bet it was 350 at the crank.
Me and a few other people where very impressed with the way it ran for no more than what it was.
A lot of people told me those heads where crap but that motor proved them wrong.
Last edited by project C4; Feb 20, 2011 at 11:41 AM.
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
have to remember also, the water pump, ps, aternator uses hp at high rpm's.
count on at least 40-50 hp loss there if so equipped as i wrote above.
i like carbs alot, very simple fuel delivery, but with todays poor gasoline at the pumps,
detonation has become a real issue just like a high compression race engine tuned wrong or too low of octane race fuel used.
so efi has to be studied harder yet and its benefits, at least by me.
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Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
That motor was in a 79 Malibu with a turbo 350.
Maybe not quite as much loss but I bet it was 350 at the crank.
Me and a few other people where very impressed with the way it ran for no more than what it was.
A lot of people told me those heads where crap but that motor proved them wrong.
Maybe not quite as much loss but I bet it was 350 at the crank.
Me and a few other people where very impressed with the way it ran for no more than what it was.
A lot of people told me those heads where crap but that motor proved them wrong.
take them off and throw them away.
but they work nice in torque production. i concentrate on making torque and wide flat power band for now.
tpi runners do that job best stock or aftermarket.
never get these engines to sing up to 7k or higher and make real hp numbers of 600hp or higher.
why waste time i figure.
people everywhere are surprised how fast my little l98 tpi 87 vette engine runs that i take for a spin.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
If you convert to a carb, your ecm will not be doing much. Obviously it will not control fuel management. Without an injector signal, it will not control spark either. I've been there, done that. The ecm sat in the cabinet after the conversion.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Quite a few people have gone well over 275 hp on the stock (ported) intake, myself included. I think the absolute limit for the stock intake is closer to 350.
Drifting
Joined: Mar 2009
Posts: 1,253
Likes: 4
From: East Wenatchee (2hours from n e where) WA
Drifting
Joined: Mar 2009
Posts: 1,253
Likes: 4
From: East Wenatchee (2hours from n e where) WA
I was thinking the o2 sensor reports might talk to the ECS and pull out timing if the AFR is wack. I did not expect that the ECM/ECS would look at the injector feedback. How does that work? would it fix it if I duplicate the injector resistance of the injecter coil with a resistor to ground? Then there is the problem of finding the resistance of the energized coil. hmmm a 1 wire dizzy is lookin better. BTW thanks very much for the heads up
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
hmmmm I was thinking the o2 sensor reports might talk to the ECS and pull out timing if the AFR is wack. I did not expect that the ECM/ECS would look at the injector feedback. How does that work? would it fix it if I duplicate the injector resistance of the injecter coil with a resistor to ground? Then there is the problem of finding the resistance of the energized coil. hmmm a 1 wire dizzy is lookin better. BTW thanks very much for the heads up
I was thinking the o2 sensor reports might talk to the ECS and pull out timing if the AFR is wack. I did not expect that the ECM/ECS would look at the injector feedback. How does that work? would it fix it if I duplicate the injector resistance of the injecter coil with a resistor to ground? Then there is the problem of finding the resistance of the energized coil. hmmm a 1 wire dizzy is lookin better. BTW thanks very much for the heads up
Drifting
Joined: Mar 2009
Posts: 1,253
Likes: 4
From: East Wenatchee (2hours from n e where) WA
I think that is probably pretty close. I an certain that you are one of most knowledgeable out there. The parameters that I am working in here is using the stock short block (less cam) and ECM. I really want to avoid having the ECM dictate valve timing. Or end up spending a lot of time piecing together a EFI system that I have very little experience with. I need to concentrate on the loose nut at the steering wheel.
