Hey guys, I am in need of some serious help to the point I’m so desperate it isn’t even fun to work on my car anymore. Ya know I got medically discharged from the military after getting injured and working on this car was suppose to keep my calm and take my mind off of things, now it doesn’t anymore, hopefully someone can give me some help here. Alright, let me first explain what I have and what I’m trying to do. I am trying to twin turbo the car. Currently I have the following parts for it. 1x 89 Camaro Iroc, 350 SBC 2x T3T4 turbos w/ internal wastegates with all oil kits, flanges, gaskets 1x BOV 1x Meth/water injection kit 1x Megasquirt standalone computer 1x electric oil pump for return line for rear mount Now, when I first started this project, I wanted to do a rear mount twin turbo setup. But started running into problems, First I only added one of the turbos. When doing so I didn’t really notice a difference other then noise, and also the boost gauge didn’t say I was making boost. It read -20, and wouldn’t even past 0. Now, the way its currently hooked up is, 3 inch pipe ran to single turbo in back, then 2.5 inch flex exhaust pipe, bought from advanced auto parts is being used for the intake to the engine. Also, the sizes of the pipe change on its way back, starts at 2inch, changes to 2.5, then when it hits the engine, it changes to 3. Now, Im wondering if its not working because either of the following, pipe size change, using flex pipe so might be leaking…or just having 1 of those turbos isn’t enough power. This makes me wonder if rear mount doesn’t work, if I really have to go to under hood mount, the only problem with that is, I blew all my money on the materials for the rear mount, so I can’t afford headers or anything like that. Here are some of my main questions…… Can a rear mount work, if I run a single 3 inch all the way to the back, then create a Y junction to split if off to each turbo. Then do the same for the intake? IF I have to do under hood, what is the cheapest way to do the manifold to turbo connection and what all can be taken out of the engine bay to make room? Currently I have moved the battery to the back seat, and removed the windshield wiper fluid motor and reservoir. Also have taken the stock coolant reservoir out and downsized. Please help me and shine some light on my project……..

A single t3/t4 hybrid will barely move enough air to feed the motor, let alone build boost. With that small of single and the small charge tubing you've likely created a restriction and may easily have lost power.

3" to the back y into both turbos should work ok, but it is far from ideal. You then need to feed back with a single 3" or dual 2.25-2.5.


For what you are doing I would reccomend front mounting them. Twin rear-mounts take alot of planning/design, a lot of plumbing/hardware and a lot of work. For front mount you could figure out manifolds to use or you can buy ebay stainless turbo headers for around $250. Especially for the $ money, they're a pretty good header. You could sell your oil pump to partially offset the cost.

I would look at the STS kits for ideas. They do use special turbos to offset the lag from the extra pipe. I installed one on a friends S-runner and the thing hauls with the low boost kit on it. I would think your best bet would be dual 2.5" back with and H pipe to feed each turbo to insure even distribution of exhaust gas to each compressor. I would then merge the 2 charge pipes from the turbos to 1 single 2" pipe and run it to the throttle body. If you look at the STS kits all the pipes are smaller then you think they should be but you have to keep in mind that you have to charge all of that pipe before the motor sees any boost. Also make sure you run breathers and not PCVs otherwise the pump can't return the oil from the turbo and it gets blown out the exhaust and this can destroy a turbo. Found that out the hardway on the toyota install. Good luck

OK, now what if I went single turbo RMT? Instead of having 2 small turbos in the back. What if I went 1 large one, with the 3 inch exhaust?

If I could do 1 large turbo, what size would it be? Like a t70 or something like that?.Like the A/R for compressor and turbine

Also, what size intake pipe should it be

This would be a rough guess on my part, but I would think that a 3" single pipe would be fine. I would get a T-70 flange and see what size the inlet is and go off of that. As far as charge pipe diameter I would still say smaller diameter is better, but then again this is just my opinion. A lot of R&D goes into turbo systems remote mounts more so. I would think a single T70 would be a good sized turbo but as far as wheel trims and sizes I honestly have no idea. Unfortunetly those decission are normally left to the pros because there is a lot of complex calculation and physics to understand behind them and to be honest I don't know enough to give you an accurate answer.