I've been thinking about fabbing up a single turbo system using the stock manifolds for my 5.3 and I'd like to make ~600 hp at the motor.

Stock, the 5.3 puts out ~290 hp so I would at least have to boost it a little over 1 bar. Will a PT-51 get me there? Or will I need a 60+ mm turbo?

I was also wondering what all would be needed to accomplish something like this, I have an idea but maybe you guys could fill in what I missed


* large single turbo, PT-51 or 60 mm turbo
* manifolds, and hot parts + flanges
* charge pipes (alum.) + silicone connectors and clamps
* 42 lb. 8.1L marine injectors
* waste gate
* intercooler
* a good dyno tune w/ wideband O2, egt monitoring etc....
* oil distributor that plugs in between the filter and the block, + oil lines for turbo
* upgraded fuel system to support 600 hp.
* 2 or 3 bar map sensor
* lots of money

I'm at a fork in the road as far as what to do with this car. I don't want to waste my time with n/a mods if it's not going to get me where I want to be in the end.

Any advice/input is appreciated. I've been giving this some serious thought lately. I can weld and fab up the hot parts so it should knock a bit of the cost down.

btw - this is in an 86 rx7

 

I have to question the performance goals of a nose heavy RX7 with the iron block 5.3 and added weight of a turbo vs. going with the lighter LS1 or LS2 aluminum block and being NA, possibly even a stroker. Seems like you could easily outperform the heavier small cube engine for a lot less money and end up with a lighter package if you went the aluminum NA route...

 

It will cost me a lot more to go with the aluminum blocked motor, especially the LS2, than to go this route as far as I can tell. This has been a very cheap project, and the added cost of the aluminum block motors doesn't seem to be a good return on investment (relatively) at the moment.

The weight difference between the iron and aluminum blocks is about 65 lbs and it all sits behind the front wheels so I'm not all that concerned about being nose heavy. I might even do a remote turbo setup, I'm just concerned about water splashing on the turbo. One day I'll probably get a 3rd gen and worry more about the handling but this will be mostly a dirt cheap drag car.

edit - to put it in perspective, just buying an LS1 would cost me twice what I have in the car already. Including the 5.3L, T-56 rebuilt by me, all of the conversion mounting equipment made by me as well, Spec 3 equivalent clutch/pp, and most of the items necessary to finish the swap. I got good deals on the car and the 5.3L came w/ a 4l60e and transfer case which I actually sold and turned a profit on the motor...lol.

 

Sooo, you're going to try to put 600HP on the 5.3 stock parts then? I don't think you're going to make the HP goals without puking the stock rotating assembly first.

 

I'll probably add some LS1 or 6.0L heads to drop the compression a bit, or get a good turbo cam and use less boost. I'm pretty sure that w/ a good tune the stock internals can handle 600 hp. I know the crank can, I would guess the weak link would be the rod bolts which aren't too expensive to upgrade.

More than likely I'll keep the boost low at first until I get a feel for what it can take. If it pukes the internals oh well it was a cheap motor anyway. Then that gives me a good excuse to get a 6.0L.

I don't think there's any cheaper way to make decent hp in my situation than just boosting it. I'll probably drive the thing around NA for a while at first...it's going to be a wild ride even at 290 FWHP.

 

You are one blip of minor detonation from having many pistons shooting out every direction. The crank is good for over 1000hp but the pistons are generally considered good for 500hp with a PERFECT tune. Go for it, it will be toast in short order

 

Never had my 5.3 dynoed, but according to the weight and trap speed I was making right at 600 hp at the crank. That was at 8 psi. The motor was completely stock except for LT and 1.85 rocker arms. It lasted 8 months at 8 psi. If I would have replaced the fuel pump it would still be running fine. Make sure you have the fuel setup that can support that kind of power and a good tune and you can achieve your goal and be safe.

 

I'm not going to start out at 600 hp but I did want to make sure that the turbo I chose was capable of that. 600 hp at the engine is probably the most I'd ever need.

So what does everyone think as far as choosing a turbo goes? I remember seeing that a PT51 could get up to right under 600 hp and that would be acceptable to me. I'm looking to buy a good used turbo for $400-650, what could I get in this range?

I was also contemplating buying two stock 86-87 grand national turbos. People sell them for cheap all day long and I know they could meet my goal. I'd rather have a large single though as it would cut down on the plumbing...