[malice10985]

I have a 99 camaro with a 3800v6. I would like to install a turbo kit, but I cannot get a straight answer out of anyone about how to properly size a turbo for my application.

I already have a fair amount of supporting modifications for a turbo application. I have Diamond 9.5:1 forged pistons and GM L32 connecting rods. The entire rotating assembly was balanced to 3.5 grams by my local race shop. It has clevite 77 bearings and 90psi oil pressure above 2000rpm. It has a double roller timing chain and the balance shaft was removed. There is a walbro 255lph fuel pump out back.

the top end is very unimpressive. I have stock cyl. Heads with comp 105# valvesprings. The cam is barely larger than stock. It is a comp 200/206 off the shelf grind. My only power adder is a NOS 100 dry shot. I would like to convert that to wet once my turbo is in place.

I would like to get an intense stage 2 or 3 turbo cam, and I would let intense program the PCM. My local speed shop can port and polish the cylinder heads. I plan on intercooling the setup.

What kind of turbo(s) should I get? Is one or two better? I have a fair deal of money to play with. I was thinking about a twin setup, with one small turbo for low RPM boost, and one big one for upper RPM. Throw some ideas my way, so I can start shopping for parts.

 

[98 TGP TOY]

Well good luck with the project.

I think your best but would be to call turbonetics and talk to them. They will work with you to pick the proper turbo or twin turbo setup. And their turbos are the best out there.

 

[eaton_rice]

http://www.turbomustangs.com/turbotech/main.htm is a great read on turbos, it covers just about all of the basics.

 

[malice10985]

Thanks for the link. I is the most comprehensive info I have read thus far.

I also found this link: www.turbofast.com
It has a turbo calculator that supposedly selects the best turbo for your inputs. It told me I need a P-trim Garrett T04B with a .69A/R turbine ratio. I have been printing out compressor maps to manually calculate the best turbo, but I think I am doing something wrong. Every turbo I pick seems to run out of steam at about 5000rpm.

I wish the kit manufacturers would release tell what unit they are using. I bet they did a lot of research and have the perfect unit.

The search continues....

 

[stuffy236]

I have Diamond 9.5:1 forged pistons

youll probably want to ditch those. The higher the compression ratio the less boost youll be able to run

Is one or two better?

two turbos are not always better. A lot of the TT Supra owners go with a single turbo setup instead of the Dual.

I was thinking about a twin setup, with one small turbo for low RPM boost, and one big one for upper RPM. Throw

Sequential turbos are possible, but how much money do you have? They are not too effiecient for the price. Plus look in your engine bay, do you think youll have room for two turbos and the piping it takes to route it to the intercooler and then back to your TB?

As for turbo sizing, check out a little write up i did on clubgp.com

http://www.clubgp.com/newforum/tm.asp?m=1737979&p=4&tmode=1&smode=1

HTH

 

[malice10985]

Stuffy-

Thanks for the info. I have had my diamond pistons in the engine for the last 12,000 miles, and I don't want to do a full rebuild. I wasn't planning on running more than 9 or 10psi of boost. I will use a single turbo instead of twins. From looking at T04 compessor maps, I think that turbo will start to wheeze by 6000rpm.

 

[stuffy236]

it all depends on what AR you get. if you get a .58 then ya it will wheeze up top, but get a 69 or one a little bigger then you should be fine

 

[malice10985]

I think .69 is a good A/R ratio for the exhaust side. I really want low end torque, but I hate it when the Engine wheezes up top at high rpm. I might go with a .84A/R instead, but then I might sacrifice low end torque.

 

[stuffy236]

its not really low end torque you lose, its spool up time. The bigger the AR, the slower the spool up but the higher RPMs you can reach without losing power. Im not too sure, but i think .84 may be a little big depending on if you want it a full out drag car or not and depending on your mods. Also, a little 50 shot of nitrous would help that thing spool up real quick

 

[malice10985]

I am definatley going to keep my nitrous. I want to convert it to a wet setup, and keep the 100hp shot, if possible.

 

[stuffy236]

100 shot is possible, you just have to make sure to beafy up the tranny. Do you have a MT or AT?

 

[malice10985]

I have a 5 speed manual tranny right now. It is only rated to 325lb-ft, and I have put 340lb-ft through it on a regular basis. It is loose and worn out. I can't even chirp second gear any more because the trans is loose. It will get rebuilt when I start tearing my car apart.

 

[gtpdude]

single turbo is better than one in a perspective but in your application i would go with one turbo and go with about a .69-.84 there are a couple people going with a .84 and are spooling up fairly descent, whos going to make your turbo manifold and have you checked out ststurbo.com how much power do you want.

 

[malice10985]

I am pretty dead set on either a .69 or a .84 AR ratio. I haven't decided which one though. SInce I have nitrous as well, I will probably get the .84 just to make sure to motor can breathe under full spray/boost.

I have looked at those remote turbos before. I think the LT1 kit is a straight foreward bolt on for my v6 camaro. Those kits just look kind of goofy IMHO. I don't see how it doesn't have tremendous turbo lag. It just seems like a waste of energy to send the exhaust all the way to the back of the car, and then pressurize the intake ducting all the way back up to the front of the car.

I have already dumped a ton of money into this car. I want something that I know works well. I am sure the STS kit is nifty, but I don't want to experiment any longer. That is why I am posting on this board; to get ideas from people who have done it before.

 

[gtpdude]

whos going to build your header

 

[malice10985]

I guess I am going to build it. I am getting help from some guys on Camarov6.com, my home forum. One guy already built himself a set a few years ago, so I am going to mimic his design for the most part.

There is another member that wants to build himself a better set of turbo headers in january, and he said he would either build me an extra set or send me the plans. I will probably use his stuff. I am not a mechanical engineer, and I can't get very creative with a welder.

If the price were right, and someone else wanted to build me a set of turbo headers, I would surely look into it. Is that what you are getting at? (wink, wink) Just remember, I am working on a camaro, not a W-body.

 

[gtpdude]

whats your price range

 

[malice10985]

I don't want to spend anymore than $300 on them, parts & labor included. I don't really need ceramic coating, or anything too fancy.

 

[gtpdude]

where would you like the turbo to mount on your car right in front of the motor or off the the side or be really cool and somewhat out the hood.

 

[malice10985]

As I am sure you know, there is enough room under the hood of a v6 camaro to host a picnic. I think the turbo would be best suited right in front of the motor, slightly offset towards the passenger side. That way it would not interfere with the cooling and power steering stuff on the driver side of the engine compartment.

The short length from the Combustion chamber to the turbo itself would minimize turbo lag, which I am concerned with since I am leaning toward a large AR ratio on the exhaust side.