I looked around on the website on porting and polishing our stock blowers, but all the post were from the end of last year, and people still didnt know much about our engines. So I was seeing if anyone else minus the couple people in those posts have recently done it and everything they have done. I am going to go to GM and get the stage 2 kit done since I still have a long time before my warranty is done. Then I will buy a 2.7" pulley to swap out with the 3.0". I am going to buy a better fuel pump just in case. So all that is left is what people have found is safe with our engines. Some people said they were around 19 psi after porting and polishing, does anyone know safe numbers. Also, I will get new headers and a new downpipe/b-pipe or whatever, probably with no cats or a high flow cat. But is there really any need to change the rest of my exhaust minus for sound since it is 2.5". I am trying to look dead stock for the most part. Should I replace anythings like cam gears or the throttle body or anything else in the engine to be safe. And I guess would doing any head work be good too and safe, like porting and polishing it. I just dont really know what I can get away with before I destroy my engine. Any help would be great, thanks.

 

bump

 

I have a Steigmeier ported blower. I don't have any issues with it, nor have I seen any results.

 

1) Porting doesn't work
2) 2.7" pulley is too small for your injectors
3) You don't need a pump, ours are sufficient enough
4) 2.7" pulley with GM tune won't work out good.

Numerous people on the RL forums have had theirs ported and there has been 3-5whp gains...for the cost, it isn't worth it.

 

ha ha ha

 

Shush! I was the 2nd person to have this done.

 

Also, no need to upgrade internals...there are LSJs out there with 350whp, which with a 2.7 you might hit 260whp.

Also, our throttle bodies are drive by wire, not drive by cable. If you mean porting the TB, waste of money too. You can change the TB to a LT1 TB, but that means you need certain pedals made by Roush for drive by cable, then HP Tuners to turn off all the codes that would be set by the TB.

 

I know I cant have a 2.7 on a gm stage 2 tune. I have a guy that will tune my car and give me an sct tuner with multiple tunes on it so all I have to do is switch out the pulley and change the tune, or tunes for better gas mileage when I do alot of city driving to work and so on. So I know that tuning is the most important part, I was just not sure if people were seeing gains from porting or not. And yea I meant changing the throttle body, not porting it, but that sounds like a lot of work so nm. 42# injectors arent too small for a 2.7 pulley are they? Or did you mean stock injectors, which I know are too small. So then it somes down to cams and exhaust. Is it worth getting cams and if I get aftermarket headers and downpipe, is there any reason to change the rest of the exhaust since it is 2.5" already. Thanks.

 

Here is the best way of gauging injectors:

3"-3.35" Pulley= Stock Injectors
2.8"-3" Pulley= 42lb injectors
2.5-2.7" Pulley= 60lb injectors

With good tuning, people were seeing the duty cycle of their 42s at the borderline of safe with the 2.8"

 

SMS "Big Bore Throttle Body" ^See above comments on Porting Supercharger.

 

Does getting that Big Bore TB offer me any gains, or will it just be alot of work to not see much?

 

The exhaust is only 2.5" to about a foot before the axle, then it is 2.25" The main exhaust restriction is the downpipe...cat or no cat, thats personal preference.

Cams...no one has done them except a couple with custom ones, but not really needed right now.

Also, you can't tune these cars with a SCT...check out their site for GM cars: http://www.sctflash.com/product_gm_xc2.php

You MUST use HP Tuners, no other way around it. The complexity of these PCMs couldn't be handled by a SCT anyways.

As far as gas mileage...it's no big deal...I get 28.5mpg and have a 2.5" pulley and 60s.

 

You won't see anything, that's why Shab said see above comments about the ported supercharger cause he hasn't seen anything from that.

 

It's no work at all really, four bolts hold the TB onto the supercharger, hose clamp on the intake, harness connector.... done. Some people report better engine response. I disagree... Seems exactly the same.

 

I heard from those that spent the money Port and polishing the SC on the Redline forums said they got Minimum gains. like 4hp next to no Trq. I don't think its worth it

 

I could see taking the head off and porting and polishing the exhaust ports helping, but the intake side won't help much at all.

Porting and polishing the intake tract is something effective on a naturally aspirated engine, but not on a forced inducted engine. The supercharger is forcing air and fuel into the cylinder. It doesn't need smooth walls and valves to get the air and fuel in easier.

But the exhaust side is still restricted. Smoothing the walls and lowering the restrictions in the exhaust system of any car is a good thing. The goal is to increase velocity. Rough, bumpy, obstructed exhaust paths increase turbulence. Turbulence lowers velocity.

Since the supercharger is forcing air and fuel in, it's effectively pushing down on the piston. Any resistance of pushing the opposing piston up (pushing exhaust out) is robbing efficiency. If you can lower the resistance (i.e. increase efficiency) you're getting "free HP".

 

Ok, thanks for everything. Yea I always saw people using HP Tuners but didnt realize I couldnt use SCT tuners. So I should mainly be worried about injectors, pulley, headers, downpipe, intake, and maybe porting and polishing the exhaust side of my head. Well that doesnt sound like much, so hopefully I can get it dynoed as is soon with only the air box mod, and then dyno after upgrades, thanks alot.

 

Or you could do a diy port for free, and i have been runing 2.7 on 42s for god know's how long.

 

I figured instead of starting a new post I would just ask on this post. I looked up about our heat exchange but didnt see much as to how much it can take. On post said 300 hp. Is that right? So unless I get to 300 I should be fine, or should I try and buy a double pass or something else. Thanks.

 

There is bigger heat exchangers out for out car, and 4-pass exhcnager.