91L98Z28

i've read a lot about the vortec heads, so i know exactly the situations and discussions about them, and don't need to re-hash that here. however, I do have a few questions that haven't been addressed before..

With nothing more than vortec heads and the SDPC vortec TPI base, I'm confident the car will pass visual. The smog guys just aren't going to notice something like that. the biggest tip-off is the egr tube block off plate on the manifold, but it can easily be spray-painted aluminum/silver to "blend in" (and besides, it's hiding under the coil). So visual is A-OK in my book. The factory EGR valve will be mounted up under the runners and hooked up and looking happy, just not flowing any EGR.

This begs the question....assuming a good tune, good fuel, etc., would a vortec-headed L98 pass california tailpipe emissions with a non-functional EGR? Anyone actually done this? I could pull a few degrees of timing out of the PROM (to lower combustion chamber temps and thus NOx, which is what EGR lowers) and maybe a few gallons of 100 octane unleaded racing fuel (again to slow combustion chamber burn and lower NOx), and with a little of that efficient combustion chamber magic... I might slip through.

Appreciate any input or comments on this!

edit: on the other side of the coin....anyone ever drilled the vortecs for EGR? i know that AFR simply drills their heads for eGR if requested by the customer (or so they indicated on the phone), so there should be a way to drill the vortec head to let exhaust gas approach the heat riser/EGR hole area...a cutaway diagram or picture would enable you to determine the angle and location of such a passage.

RB83L69

I've been through California smog inspection a few times.... I think it's safe to say, a non-existent EGR valve won't "slip through". It's the very first thing they look for.

But yes, it is easily possible to make a car pass the sniffer test without it, usually. It kind of depends on what the rest of the motor is.

It's impossible to predict whether a given head casting can have the crossover passage drilled into it. Without seeing it, you wouldn't know whether you were going right through a water passage, or if the place on the intake flange was nothing but a flange and isn't even connected to the rest of the head at all (i.e., if you drilled through it you'd hit crankcase). It's all in how the casting is arranged.

I think you'd have to be either some kind of fool, or optimist (the same thing?), or a real glutton for punishment to build a motor as expensive as that, that is blatantly non-compliant with the laws to a visual inspection (that is, open the hood and look at it, and duh..... ), and just trust to blind hope that nobody's going to notice. You're probably not the first person in the history of CA smog laws that has thought that, and probably won't be the last either. Plus, you'd have the issue of the ECM, I'm sure that with the EGR simply missing, you'd get a constant Check Engine light..... guaranteed you'll fail for that too.

I think a much more intelligent approach would be to prepare yourself for doing it right, before the motor is in there and doesn't pass, and it's easy to set it up, and you're not walking to work yet because your car can't be licensed.

paulo57509

Just my two cents...

You might be able to lower the combustion chamber temp and thus NOX levels by tweaking the timing, but they do check for proper base timing adjustment.

I just had an enhanced test done and they guy did pull out the old timing light.

I agree that the Check Engine Light would raise a red flag.

You might be able to pass this one time, but when the enhanced test goes into effect state-wide (has it already?), you're bound to get pinched. Keep in mind that with the enhanced test, your car will be running on rollers....with the ECM controlling timing. I'm sure the higher NOX levels will show up here.

Dyno Don

iTrader: (7)

There is no way to drill as the area is blank ( unlike the AFR's).
However you can add the EGR tube connected to the right side header and say the motor is a Corvette. I've already done that and passed.

91L98Z28

Just thought I'd clarify a few things about what I was asking!

RB83L69: Wasn't implying that I would leave the EGR valve off. The EGR valve would still be mounted to the center of the intake, just like normal. The only visual difference would be the EGR passage blockoff plate (underneath the coil on the corner of the manifold) which they would never notice (because it's not supposed to be there, and I'd paint it to match the intake, and the coil is directly above it hiding it from view). With the EGR valve present, the ECM would be happy because the vacuum sensor that "checks" EGR operation would be hooked up and operational. Irrespective I can just disable the EGR entirely in the ECM (i can burn my own chips).

paulo57509: I can change the timing in the chip. The base timing would still read correctly - which is all they check. THey don't check the timing with the computer advance hooked up, which means I'm free to do anything I want with it in the chip (and thus control timing on the treadmill portion of the test). I'm already on the enhanced test and have been for years.

Dyno Don: Are you in an enhanced area and do the treadmill part of the test? If so, that is great news and it solves my problem! What did you have to go through to get them to test it as a vette engine? Did you relocate the coil? It appears that the SDPC EGR tube thingy occupies the same space as the coil.

Oh, and I'm not talking about building up an expensive motor here. My motor has 92k on it, and the bottom end is SOLID (good oil pressure etc.), but the valve guides and seals on the heads aren't so great (puff of blue smoke at startup). Since I intend to replace the stock intake anyways (wether I use the SDPC or accel is a wash in terms of cost), AND i need to at least have the heads rebuilt ($200-$300)... My thought is, why rebuild the stockers, when for $200 more I can bolt on the vortecs and 20-30hp? The 0.480 lift problem is not even a concern - i'll be running this on a stock cam.

RB83L69

All I can say is, good luck. I wouldn't bet the farm on it myself. You seem pretty convinced you can get away with it and I guess there's only one way to find out.

I lived in an "enhanced" area myself, north SD county. I was able to redefine my personal definition of "**** retentive" when I took my out-of-state car through inspection the first time. They "enhanced" my attitude real good, I can assure you.

91L98Z28

Yeah. I'm fairly confident (about 85% worth!) that I can get past the visual without a problem. Most smog shops I've been to, don't get nit picky unless there is a reason to get nit picky. if everything looks stock, they just breeze through the visual tests. As soon as something is out of place though, they start checking details...

My concern is the actual tailpipe, because (if I skip the external EGR tube and make it visually appear as totally stock), i won't have any egr at all... thus the control of the NOx is gone.