GTA Sammy

iTrader: (1)

Thanks for lookin in.....

I've been thinkin about doin a Rear Mounted Turbo system for a few years now..... (All my friends run turbos ) ....... & I'm sure it can be done because a few have done it sucessfully, let alone the STS craze.

Now I know that a RMT will never be as thermally efficient as a front mounted system...... and I'm not about to argue that it is....... But I've just got too much $$$ into my exhaust (Coated long tube headers/Custom Y-pipe and 3" Flowmaster Catback) to throw them aside for a front turbo set-up!!!!

So I've been doin some homework about the RMT stuff and think that a ball bearing unit would be most appropriate...
I don't want a slow spool (don't laugh...) and was looking at a Garrett GT35R look here.... http://www.atpturbo.com/mm5/merchant...egory_Code=GTH with a .82 A/R Turbine
Flows upward of 60 lbs/min for 600Hp http://www.atpturbo.com/root/maps/gt35r.htm

I was looking for a street car with about 500 RwHp......... Don't plan on this current engine lasting me long and will eventually build a Forged 383 HSR engine, with better fuel system and stronger Tranny and rear.........

But in the meantime...... sorry for the RANT!!!
What do you turbo guys think about the GT35R??? In the rear? Thanks!

HCR13

iTrader: (5)

I think it'll be a great idea! I still have to bolt mine up. Sadly my LB9 blew. I was able to get a 350 replacement. When I got home I noticed it had new .030 forged pistons, once thats installed and running, I'll bolt up my rear mount...

RoadHammer

Personally, I am not a fan of rear-mounting turbos, however, there are guys making 10-second 1/4 mile passes with them.

The common thing I see in some of these RMT builds are that the turbine A/R on the turbo is quite a bit smaller as compared to a turbo for a FMT. Take a look at the turbo you get in an STS kit and you will see what I am talking about.

Also, google "quick spool valve". supra guys use these to spool the stupidly large turbos they put on. The idea is that the valve (a basic butterfly valve) creates excess exhaust backpressure to "dump" all that excess pressure to the turbine, thus making the turbo spool quickly. Guys with RMTs are using this to the same ends.

If I were to do one, I would examine the parts required and research ways of maximizing spool. I would incorporate a quick spool valve, have the exhaust tubing from engine-to-turbo ceramic coated, isolate the turbo's oiling system from the engine, and would seriously look at custom turbo sizing and talking to a company that custom builds turbos to get their opinions and advice for the RMT application.

Just my opinion.

HCR13

iTrader: (5)

I think there are pros and cons to both systems. Each system has been proven to work just aswell as the other. So its a matter of preference or availability. One thing that I do love about the rear mount is the sound!

83 Crossfire TA

iTrader: (2)

Work as well... no. Works... sure.

What's wrong with .030" over pistons?

Anyway, I know, that's not the question... gt35R... I think it's a pretty good choice. I personally think that there is still a lot of guessing involved in picking rear mount setups, mostly because you end up with a lot of plumbing between the engine and turbo and a small change, a change in materials... will change how it spools.

Personally, I would not only choose a smaller turbine A/R but a smaller compressor then you would otherwise, and that is definitely what you have there. I believe that some of the rear mount setups are running turbos with turbine A/R's in the .6x range (don't remember what turbines are available that small, maybe .68?), but my instinct is generally what you loose in response with a slightly large turbine you gain in efficiency- things get hard to tune and keep happy when you block the exhaust off too much.

Do it, post a build thread, show us how it goes. Worst case you might end up having to wrap the exhaust or swap for a smaller turbine side.

HCR13

iTrader: (5)

I plan on doing the rear mount turbo for a while and then swap to a front mount. Then I'll make an opinion as to which is best... The reason I'm doing this is because I already have everything needed for the rear mount. Eventually I'll save up for the bbs headers and go from there...

Orr89RocZ

iTrader: (20)

There are some vette guys in the 8's and I THINK 7's with twin remote mounts so I would not be concerned with efficiency. When in doubt just exhaust wrap your pipes.

GTA Sammy

iTrader: (1)

Thanks for the input Guys!!!!
Tax time is comin & I'm planning on a healthy return....