When you swap to high flow heads, like trick flows or something..

What exactly is it in the prom that needs to be modified to accomidate them? Will the car run *right* without any prom mods? are the mods just to get PEAK power out of it?
What is it that i'd be changing in the prom for the swap? Thanks!

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1985 IROC-Z
TPI 305, 700R4 with shift kit, richmond 3.73's, auburn pro series posi, crane compucam 2030, ported plenum, gutted air boxes, all the little insignificant stuff.

 

More air equals more fuel. If changing the cam also, then you may have to add fuel here and possibly take fuel out there. The only true way to find out is to look at scan data.

 

Well thanks, thats a given though.

What i mean is what fields/tables are you focusing on?

Also doesn't hte computer do everything it can to keep the AFR at like 14.9:1? or whatever you set it to? so wouldn't it dump its own fuel?

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1985 IROC-Z
TPI 305, 700R4 with shift kit, richmond 3.73's, auburn pro series posi, crane compucam 2030, ported plenum, gutted air boxes, all the little insignificant stuff.

 

It depends on what ecm you're using. I am only familiar with the 730 and the VE tables would be the things to change. On a MAF system, there are no VE tables so I guess it would be the LV8 tables. These are the main tables responsible for fuel calculations but you also have other things that can be affected by a head swap. For example, if going to aluminum heads with the same size chambers, you may want to add more timing or more fuel when cold or any other number of things. If you want me to tell you everything you need to change, I simply don't know nor would I think I would if I did. This is after all DIY and it's learn as you go. I am not trying to be a smart *** , I'm just trying to be realistic. No one knows everything.


That's the key: it does everything it can. What does it do when it can no longer add fuel? By changing things so that it doesn't have to search for the best settings, the car will run better and have a wider range of adjustment in case something changes. This is the reason why we are here and go through the process of learning. If it were as easy as letting the ecm compensate, DIY wouldn't exist.

 

What might seem to be a smart answer, which isn't, everything.

The oem calibrations are generated for the lowest common denominator of driver, with 0 maintance.

Now with a different engine you need to redo the timing tables (generally LESS timing in PE), leaner AFRs, in non PE mode (power enrichment). Then a whole new set of low rpm stuff if you go to a looser converter to match the engine modes.

The aftermarket stuff in general changes is poor at best. You have to tune everything to get the perfect chip, once you drive the perfect chip, you'll understand why all the work.

 

Ahhh... the perfect chip..... tis an elusive little bastard....

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1987 GTA L98 MD8 GH3
355 '97 Vortec 4-bolt block, TRW(suck) forged pistons 10:1 CR, TFS 23*, LT4 Hot Cam, Ported plenum and intake, SLP Siam Runners, BBK 52mm TB, Edelbrock TES, gutted Cat, Flowmaster, CAI w/K+N cone, AFPR, TB bypass, !AIR, !A/C, !EVAP, ARAP, 2300 stall, Alum. Driveshaft, Hotchkis STB, '99 Camaro seats.

Coming Soon!!: Fourth gen 3.42:1 rear, Spohn LCAs and Panhard.

 

Yea.... anywho





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1985 IROC-Z
TPI 305, 700R4 with shift kit, richmond 3.73's, auburn pro series posi, crane compucam 2030, ported plenum, gutted air boxes, all the little insignificant stuff.