Has anyone here either made or know where to get a CAI for a turbo sunbird? Mine is a '90, and I would like to get more power from it.

Another thing I am having difficulty with is that when I push the pedal down more than 3/4 of the way the turbo seems to cut back, or it could be the fuel cutting back. My best power seems to be just before this happens, and if I hold it there I get real strong acceleration. I am running almost 13 psi of boost right now, but it will only hit that breifly before it cuts back a little (I nail it and it hits that then the cutoff hits right after), then it goes back to just over ten psi. Any suggestions? Thanks.

As for the CAI the easiest and best way is to take a universal filter and mate on a pipe the same size as the turbo intake and just bolt that up, only about 8,9 inches of pipe maybe. Prontus had this setup and its what i'm planning on doing. I'll see if I can find some pics of his setup.


<img src="http://www.geocities.com/fudd_22602/elmer-shoot.gif"> Old school Js rock

pics of Prontus's CAI










<img src="http://www.geocities.com/fudd_22602/elmer-shoot.gif"> Old school Js rock

Sounds like you're hitting the fuel cut out and need to bleed boost off at the vacuum hose to the MAP sensor. It varies a bit from car to car but typically between 10 and 12 lbs you need to bleed boost off or the computer will trip you up like this. Are you getting a code 31? You should be.
If you're already bleeding it off you could be getting detonation but usually that'll sound like "sneezing" from the intake tract. Make sure you use the highest octane fuel you can get to avoid that.

Tony


Tony
1987 Sunbird GT turbo convert
Ported intake, Fiero 53 MM TB, 52 lb inj, ported and flowed head, tube header, Mitsu TD06, ARP rod
bolts/head studs, adj cam sprocket, 4" x 12" x 31" FMIC, Paxton AFPR, modified 125 trans/LSD
unit/3.42's, custom chip tuning, Alky Control Methanol injection
13.61 ET at 101.44 mph, 262 WHP/350WTQ

2009 Pontiac Solstice GXP roadster, 2.0 turbo w/GMPP exh, CAI and turbo upgrade, 290 hp/325 ft lbs

1969 Olds 442 convert
400 Eng, 200-4R trans, 3.73 posi, power everything, OAI

mine is similar to that, but i have a 90 bent in to it and it stuffs up higher to keep it from getting as wet. actually, as it sits now, i have it stuffed up through the hole into the engine bay (i'll never run through the winter with my filter low again)


WARNING: I bring nothing to the table.

Cool, this gives me some ideas. I also noticed the intercooler set up, and I think I'll give that a try too. I already use 93 octane gas all the time, and sometimes use some octane boost, so I haven't had a big problem with detonation. Once I used 89 though, and I found out in a hurry I had to take it easy and not let much boost build.

Hey look the underside of my car, lol.

While I like my intake alot - something you'd have to bare in mind is that isn't a stock turbo and sits a few inches lower then the stock turbo does. Also - I had to notch part of the body in order to get that tube to be straight.

For a stock turbo'd I'd just clamp a filter on the stock airbox and make a heatshield for it.. others have done this.

As far as your fuel cut - as tony said you should be getting code 31 - are you getting any codes? Do not ignore them! this is ODB-I they are all pretty much important to varying degrees.

Yes, I am getting a code 31. I'll also try that with clamping the filter on to the airbox, and I have a custom heat shield that clamps on with the filter, so I should be okay there. When my old turbo went bad they replaced the cartrige at the turbo shop (the guy charged parts + 10% so it was only $336), and the guy said he put something bigger in for me so I would have more fun. I know its still the same water cooled Garrett set up, but I dont know what else will fit in the same housings, so I dont know what he used other than it was a Garrett brand replacement. I did notice a big increase in power though. I need more now though.

Engine rebuilding is easy, but I'll admit I dont know tons about turbos, so I'll take any advice from someone who has more experience with them I can get.

get a bigger turbo. you cant have a whole lot of fun on the stocker


WARNING: I bring nothing to the table.

There doesn't seem to be a whole lot of agreement about what works and what doesn't work for the turbo 'bird.

I can give the following pointers based on my experiences. I have an 89 turbo Sunbird which runs 12+ psi, and a 93 Cavalier 2.2 with a home grown turbo install using a Sunbird turbo and ecm.

I have found the following:
The bottom front of the engine compartment gets very wet during rainstorms or snowstorms. If you use the car all year long, take this into account. Water hitting a turbo compressor wheel spinning at 100,000 rpm+ will do damage. Salt water from the road in the winter will do more damage.

The stock 'bird turbo isn't as poorly sized as claims imply. On a better flowing engine such as my 2.2, that turbo will behave completely differently. On the turbo 'bird the stock turbo seems to "flatten out" at under 5000 rpm, but on a larger displacement engine with better flow, the same turbo continues to move air and add power until I shift, well after 6000 rpm. With that info, I cannot say that the stock turbo is the largest limiting factor in the turbo bird's performance.

An intercooler is a great idea if increasing boost. I have logs showing how much my intake air temperatures dropped after adding a small cooler to my 'bird. You can improve spooling, improve mileage, and imcrease engine durability with a good intercooler install. My Cavalier is not using an intercooler right now, only because I want to prove that a 2.2 can be run without one and still be reliable. But I will add a cooler to that car (and increase boost) shortly after I decide that I've proven my point.

The turbo car calibration tends to add a bunch of fuel. I believe this is to make up for not having an intercooler. When entering "power enrichment" mode, the turbo calibration commands an open loop afr of approximately 12:1 AFR, and the "boost adder" fuel strategy enriches the mixture beyond that. To me, it sounds like several things are happening in your car.

1) Pressing the throttle heavily, past 75% or so, forces the ecm into power enrichment mode. The engine runs a bit rich, makes less than best power, builds boost slower, and doesn't hit the fuel cut. But it's safe and doesn't bring the engine back to GM for warranty work (not that warranty matters now).

2) Pressing the throttle to less than 75% does not force the ecm into PE mode. In this case, the ecm is still commanding 14.7:1 AFR. Don't choke, it's not a bad thing to run 14.7:1 under boost. As long as there's no detonation, the engine will be fine. As long as exhaust temperatures stay reasonable, the turbo will be fine. In this mode, there's more heat in the exhaust (than in PE mode) which causes the turbo to spool faster. The turbo spools faster than the programmed values for wastegate control in the ecm anticipate and the ecm fails to accurately control boost. Boost builds to an extremely high level.

This is a common issue! If you read through the SyTy archives (the Syclone and Typhoon use the same ecm and same turbo code as the turbo 'bird) you'll see this type of boost spike is probably the most common issue with those vehicles. And to be honest, every change you make to the airflow path in your engine will further decrease the chances of the wastegate tables being correct. Better intake, better exhaust, better anything will affect the wastegate control. C'est la vie... this is the way it is. Boost control can be a completely different battle than making more power.

3) When boost is high enough, for a long enough time, the ecm commands a fuel cut. Fuel is shut off for a preset time and the exhaust manifold cools off. As fuel delivery is resumed, the amount of increase in manifold pressure is slower. Boost doesn't build faster than the wastegate control tables are prepared for, so the ecm can better limit boost to the programmed amount desired. You see the boost gauge again climb, but it stops at a "measly" 10 psi.

If you get into chip reprogramming, there are many changes which will improve the overall performance of these cars without forcing you to buy a larger turbo. My manual trans 'bird now behaves extremely well, yet has enough power to ... well, I won't mention any stories in case law enforcement is listening. Now that you already have a larger turbo, you could really do wonders for your ride by learning to make chip changes.

In the end, it's all about what works for you.
-->Slow

Thanks for all this info. I drive my car year round, and when there's snow and ice I always drive it since my other car absolutely sucks on slick roads. I see that I can not put the filter down low like in the picture above since if I do I will probably ruin the engine by sucking water. I definately do need an intercooler. I found one from a Saab 900 for 25 dollars, so I may try to see if that will work for me. If not, then ohh well. Since I have an extra computer for my car where can I get a chip done for it? I know I need to wait until I get everything else done first, but the more info I have the better prepared I'll be. Again, thanks for the info.