I have a 350 with vortec heads and I would like to know what problems I'm going to have with the tbi setup I'll be using. My 91rs will be the recipient of this engine and I will have to run the stock chip for a while. I just don't want to hurt the engine before I can get a new chip burned.

Thanks for any help on this swap.

Steve

91RS, 350vortec, 454tb, Headman shortys, RPM Air Gap, 3"catback, 323posi.

 

I'm not sure I understand the problem.

If you build an engine that doesn't use a EGR valve, it won't hurt anything. (except the smog police's feelings )

With the stock chip, you will probably get an EGR code but I can't see how engine damage would result.

Is that what you were wondering??

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

R.I.P. #3
My favorite quote about D.E. "He can see air"

 

This engine is out of a 96 Tahoe and originaly had egr from the exshaust manifold via. metal piping to egr valve on intake manifold, so yes it had egr and if I can run without it I'd rather do that. Fortunatly Tennessee dosn't have smog police

Steve

 

The only thing that you may notice (besides an SES light) if you removed your EGR is that you may not be able to run as much spark advance and gas mileage will decrease.

The EGR fills the cylinder with "inert" exhaust gas when in "part throttle cruise". This does two things: 1) makes the engine have effectively less displacement as less "good air" is filling the cylinder and 2) you can't run as much spark advance.

During a "cold snap" when the temperature got REALLY COLD, I noticed my EGR stopped functioning (until I modified the "EGR ON Temperature" within the eprom. When the EGR was not functioning, my gas mileage dropped about 15-20% and I had a LOT more occurance of "knock retard". Lowering the EGR's Enable Temperature cured both of these problems.

I gained a whole new respect for EGRs after that. And now that I have invoked Highway Mode (thanks to the EGR), I am running 17,6:1 and 47* spark advance at speeds > 40 mph and < 73 kpa of MAP. I can actually climb a 6% grade and remain in Highway Mode without ANY knock retard occuring.

 

So would changing to an open element and getting rid of the smog pump and all air tubes (as I have done) disable the egr?? So i'm getting worse gas milage now?

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Pat Hirsz
www.iit.edu/~hirspat/MyPage2.htm
88 305TBI
Mods:Hooker Aerochamber 3" exhaust, gutted kitty, March pullies, no smog, 180 thermo,
14x4 K&N, 3.42 gears,
Eibach springs with KYB's all around,
Harwood cowl hood, Z-28 wing, fresh paint(black)
120,000 miles, 5spd, T-tops
Run a best of 16.7 @85mph before gears, slp headers on its way

92 RS, 305TBI, auto, 3.08 gears, 180 thermo, glasspack (no muffler)

 

I was hoping that the vortec heads with their better or more efficient combustion chambers would help me in this area. it seams to me that if i were to build an engine for say a 69 camaro an not run egr this would not be a problem. I know the advance curve would be different than say a comp controled car but would it really be that much less efficient? How did they get along without it for so long other than 100oct premium gas. Daaahhh, I guess I just answered my own question. Anyway I guess I,ll find out soon enough.

Steve