Yeah I'm gonna stick with the Maf sensor, there's been issues tuning the car without it I've heard. And no I'm not gonna go stand alone, atleast not untill I build the engine. If I had the money right now I'd make this thing so fast lol. I'm hooked on speed lol.

 

I know what you mean.

A turbo swap is a lotta cash, time, patience, and fabrication. I got to participate in building a turbo swapped redline and it was fun, but took a lot of labor and is still in the process of working the bugs out. Its definetly not a weekend project by any means.

 

I'm thinking too, that it would be better to get a LT1 maf sensor now to. Do out know if the ID of it is 3"? And turbo piping, what's the best size there? 2 1/2"? I'm going to start ordering parts soon. Just want to make sure I get the best stuff out of the money I have.

 

I beleive the stock LT1 MAF is 3.5" but dont quote me on that. On the other hand you could always go Megasquirt and be a pioneer in the Cobalt World!!


As for things like IC piping I would say 2.5" is going to be the optimal for the setup. Also choose your FMIC very carefully based on flow abilities and efficiency. Also I would make sure your using a bar and plate and not tube and fin as they are not quite as efficient.


If you are really on a budget you can buy kits like this from ebay... (not the 100% best quality but they will sustain 350HP). They provide the basice of what you need to get the job done.

FMIC PIPING KIT




Also for a budget FMIC look to Godspeed IC's on ebay. Here is an example.


Ebay Godspeed IC

 

Actually Steve I was going to keep the stock air/water intercooler. Mine is already changed over to dual pass and a extra coolant bottle for more capacity. It's supose to be very efficient from what I hear.

 

Yes air to water intercoolers are efficient; although they only provide this cooling effect for short intervals. Air to air provides better cooling for longer periods of time.

I don't have a point to what I'm saying other than explaining to you the positives and negatives of an air to water intercooler. They are highly efficient when cool and lose efficiency as you push the engine. I would say for a drag/street setup it will be ideal as you will not have prolonged run times .

 

That will work then!! Good deal.

 

exactly, alot of people don't realize this. For a road course car, you will usually like a big front mount air-to-air best because act's will stay pretty consistant as that is the least prone to heat soak. You will get the best performance in one instant from an air to water with ice though, which is ideal for a drag car. I am not familiar with your cooling system, but if it is not already possible, work on setting up an ice container or get ice into your water tank. You can drastically drop act's by using ice thus increasing performance.

p.s. many air-liquied intercoolers use a mix of water and coolant in the same tank. if this is the case on your system (im assuming it is) REMEMBER ICE MELTS.

 

Yeah ice can be very beneficial. Another reason why air to water intercoolers are good for a drag/street setup is that it eliminates most charge piping and the pressure loss of a big intercooler. This will help response; so for a quick drag race this is the way to go.

 

true again, and you save weight in the front by having less piping! WHEW FOR AIR TO LIQUIED!


edit: wait nevermind i forgot you guys aren't looking for weight transfer to the rear like i am lol.

 

K well i did all the hard work. plotted points at 12, 18, 25 PSI on 3 different turbos.
I assumed that the cobalt would start making boost at 2800rpm and would be at full boost by 3500rpm. If someone thinks that it would spool at different RPM's please contact me and ill edit the graphs.

 

Edit: I had a confusing post here so I'm going to edit it to be easier to read. By plotting the pressure ratio at the RPMs you did it appears as though you will experience turbo surge even though you won't. Your plotting is good but only if you can read the fact that you could draw a line almost up the middle towards your highest and furthest right plot (look at the dotted line).

Ignore the 5.0L engine plot. If you plot like this you will be able to show a close to linear representation of the pressure ratio building as lb/min increases with rpm etc.:

[IMG][/IMG]

 

I have logs somewhere from Dans car with the Holset turbo swap showing a consistant 100 degree temperature drop via the bone stock LSJ air/water cooling system. Hot day shows ~220 output temp from the turbo (via blow-through MAF) and map (IAT2) was showing ~120 very consistantly. Temps did not fluctuate hardly at all.

An additional heat exchanger and/or dual pass endplate will only further improve those temps.

 

I'll be sticking with the stock system with my second h/e as well.

 

How about you guys Look at this. This is a screen shot with a gt2871rs @18.5psi
This car is way faster than a stage 2 at almost the same boost levels with conservative timing.
I haven't gon back on the dyno to get actual numbers,but we feel this car is making close to 340whp as it stands




this is a stage 2 car with a 2.8inch pulley days apart.

 

Sales@rebelautoworxs ---- Nice graphs there. How much long term testing and tuning have you done on that car? Have you thought about playing with the GT3071 or any other combination of turbo's?

 

I'm getting a woody looking at the graphs lol. Nice low IAT2 temps compared to the factory sc.

 

2.8 running 83%?
what injectors?!?!

 

I kinda understand you but could you please explain a little better. Thanks

 

Car has been running for about a month. Has been to the track.. Runs better than the stock the owners says.
The Gt3071 is going to be a tight fit back there.. besides the Gt2871rs is we are using is rated to 440whp. It has a precision front cover that is larger and a Precision .48 rear hosuing that apparently flow like a .68
Spool time is Excellent.with 18.5psi and less timing timing we are very happy with it on the street and it will live a long time. I'm sure we could end up making near 360whp with 21psi.and 17-18 degrees of timing. Oh also the Iat2 temps are with factory cooler setup no dual pass!! or extra heat exchanger!

 

This is an excellent informative thread. I figure within the summer enough people will have gone turbo to give some actual numbers to make us all drool. It Would be nice to see this thread condensed and stickied.

I am also lucky enough to live near someone who is going turbo so I can see first hand.

 

hey rebelautoworxs im sure EVERYONE on here would LOVE to see some pics of the setup.

 

What did the turbo car run at the track? I think this car would be so much easier to launch if it was turbo too.

 

eh....maybe. Turbo's often create quite a bit more torque than blowers. Usually not quite as quickly, but it is still there, and the extra torque in first gear is still gonna give you major traction issues. The initial launch may be a bit easier, but as soon as you get that turbo spooled in first you are gonna have issues without major traction mods.

 

15.4 @108mph it wasn't shifting into 2nd.. he let out and coasted to shift the car into 2nd gear having issues with the clutch ..
Pictures let me see if I can dig some up.