I am going to put twin turbos on my 350 TPI Iroc. I've searched all of the past Turbo entries so I'm catching on to what needs to be done. I have a few questions and would be great if someone could help me. What is the purpose of a wastegate? Is it a blowoff valve for the exhaust? How are they controlled? I want to use two small intercoolers located up behind the fog lights. I plan to make some air ducts that will move cold air through them. Is there any flange that would join the two pipes after the intercoolers into an oval shape so it could go into the intake? What turbos are good to use? I don't want to go over about 8 lbs because my engine is stock. Any other tidbits that I should know before I jump into this would help me greatly. I plan on getting a junk car from a junkyard to mock up all of the set-up so my car isn't down for months.
Thanks

 

The wastegate allows some of the exhaust to bypass the turbo to contol turbine speed. It uses a boost pressure source on a diaphram to actuate a valve. They are controlled by the amount of boost that gets to the diaphram. An adjustable bleed allows you to control that boost signal.

Probably best to fabricate your own pipe for that merge you are talking about. You can purchase oval pipe with mandrel bends or you could cut a standard pipe in half and make your own oval pipe... you could even flaten a larger diameter pipe to make your oval.

As far as turbos go, I'm using PT-51's from http://www.precisionte.com . If I were going to only build 8# on a stock motor I'd go with a couple of stock grand national turbos or a pair of T-04's. The junk yard turbo guys like the turbo mustang units off the manual cars.

Aside from that, I'd suggest looking into the banks manifolds that are supposidly still available. They will save lots of frustration. I finially finished my manifolds out of schedule 40 weld els... they make for a high quality manifold but the thick wall tubing is a huge pain to work with... not to mention expensive. I'll have $240 in materials in them... Thats not counting tool costs machining the flanges or welding.

What are your plans for the fuel system / tuning?
I'm thinking a FMU would probably be ok for your application.

 

Thanks for your repsonse that answers alot of questions. I was figuring either run bigger injectors or do like the callaways and have two extra injectors in the intake pipe. Can i just get a bigger fuel pump or two fuel pumps and crank the pressure way up?? As for the coputer, I read in my search that you can use a turbo computer and re-pin the harness, then use a 1 Bar map. My car is speed density, is there anything different about that? Oh and also can't I get a pc interface because I already have an Auto-Tap, could I burn my own programs with my laptop??

Thanks again for your help.

A side note: I found these great intercoolers from a Saab turbo. They are about 12" x 18" and would fit great I think. http://cgi.ebay.com/ebaymotors/ws/eB...tem=2407745992

 

Well, one of my other cars is a saab, and most of the saab guys ditch those in favor of higher flow units from a saab viggen (special model). But these are guys running 22 lbs of boost on a 2.3 liter 4 cylinder. If you use 2 and keep your boost down between 10-12 lbs you should be just fine. As for fuel enrichment, a lot of guys these days are using alcohol injection as it lowers intake temps and provides fuel enrichment. Another thing is propane injection, which also provides fuel enrichment, cools the intake even more, but is a bit more of a pain in the but to set up. Check out
http://www.geocities.com/rad87gn/tech/SteveCkit.html
http://home.att.net/~stevemon/AlcoholInjMod.html
http://members.tripod.com/alcoholkits/
http://www.dynamicracing1.com/ (and look under propane injection)
http://www.importpoweronline.com/propanecontent.html

The benefits to both of these is increased octane, so less detonation worries.
Hope this helps.

 

I would agree to either get the Banks manifolds or if you are still in limbo with piecing everything together..hold off a little longer because Banks told me the TT kit is finished for re-release and the final bugs are being worked out now...that may be your best bet to get a complete kit and avoid all the hassle

 

I was reading that site about the "ProPain" kit, and was curious if the same laws affect a gasoline motor? I know you can run propane injection on a turbo diesel practically forever and not damage anything, do the same rules apply to gas?

Balael

 

Kinda cute!

 

Thanks for all your input, you guys have been a great help! Please, if you feel you need to add something or have an opinion about it keep posting.

 

Sure - read the Corky Bell and Hugh MacInnes books.

A.

 

Geeze Andris, it's like you're awake from the dead and you've suddenly posted in every thread that I've been subscribed to all in one night...

 

He he he. I finished off a cup of coffee around 4 pm yesterday, and was still wide awake at 3 am...

A.