1point3liter

Hey,

Basically, I miss my old turbo setup. Nitrous is a lot of fun, but it doesn't compare to the feel and fun factor of a turbo. I'm still learning about ls1s and piston engines in general. They are definately a bit different than the rotaries I'm used to building and blowing up.

I have a few ideas, but really need a lot of direction. I'm looking to make around 600rwhp and need advice from those of you who have done it. Obviously since the ls1 is in my rx-7, a custom kit will be fabbed.I just pulled the engine on saturday with plans to prepare it for boost.

Here's what I'm thinking.

A set of low compression forged pistons, arp rod bolts, and stock rods. From what I've read the stock rods appear to be strong enough. Anyone else have a different opinion?

I'm thinking about maybe a t-66 if I have room. Any advise here?

Are there any limitations with ls1edit that I should be aware of? How much boost will the stock map sensor read? I'm assuming 14psi or so.

How much boost will it take to reach around 600rwhp?

The car currently weighs in at 2700lbs with half a tank of gas. I'm planning to add a roll bar along with the turbo setup. Hopefully the end result will be 2900lbs at most.

At the momment I have 4.10 gears. I'm in the process of hunting down an autmatic 3.9 rear end. This is the best I can do for gearing unless I want to buy aftermarket 4.33's or 4.7's which obviously aren't going to help. My only other option is to fab in a different rear end that has a wider gear selection. Since I want to keep my IRS, this will require a lot of bling, so take into mind that for the momment I'm stuck with 3.9's. and around a 26 inch tall tire. Traction is currently no issue, the car will dead hook from 45mph on the bottle, but I'm concerned with the short gearing and the turbo.

Sorry for the novel.

Thanks!

1point3liter

One one thing I forgot to mention. Due to my limited gearing, I really want to spin this engine as high as possible. 6800rpm maybe?

I'm currently running a TR224 112 cam. I would imagine that a spit pattern cam with a high LSA would be preferable. Anyone have a recommendation?

1point3liter

Anyone? I'd really like some input so I can go a head and get a set of pistons in the mail.

smokinHawk

iTrader: (48)

there was a guy in columbus that put a supercharged ls1 in his 3rd gen rx7, but he doesnt get online that much.

anyways first off.
the T66 probably wont be big enough, id use a T76 should be good to go for 600rwhp
pumbing would be some work for you as i dont know how much room you have with the ls1 in your rex, unless you already have it in there.

as for edit, you should be fine with it at 600rwhp after a little more then that the factory MAF meter can only read 60lbs/min so its hard to get past that point with out a piggyback

for your cam the 224 would do ok but id go with a higher lsa like 114-116 instead of the 112.

what tranny are you using?

smokinHawk

iTrader: (48)

for your CR what octane do you want to use
id perfer something close to 9:1, but i use 94 octane.
if you want to lower the octane requirements you could go lower, but ofcoarse you be a bit more laggy till boost, and spool time be shortened.

Excal

many supercharger guys spin beyond 7000rpms, so you can consider that as well

1point3liter

I've heard of the car and seen a couple pics, but that's about it.


I'm pretty sure I have enough room. Has anyone experimented with a T-66? The T-76 will be a tight fit. What spec t76 are most people using?


Thanks for the input, I will most likely sell the cam.


I'm using a t-56


I'd like to make around 575-600rwhp on pump gas at 9:1, but have considered 8.5:1. I'd prefer to keep the boost curve more linear so the car is still autocrossable etc. In addtion, I'm sure i will be running race gas on ocassion, but don't want to rely on it.

What pistons are most people using? Do you see a problem with me using stock rods with arp rod bolts instead of a forged set? Do I need to oring my block or consider 6.0L truck heads?

Pro Stock John

iTrader: (34)

Nice project, I like the RX7/LS1 hybrid.

My responses:

I make 746rwhp on 17 lbs of boost on a forged 9:1 348ci:

stock crank
3.905 -8.6cc Diamond Pistons
6.0 ported heads, 2.02/1.57 valves, flow 300/225 at 600 lift
230/236 FMS/ Cam Motion cam, 115 LSA, 3.5 degrees of overlap @ .050
Eagle 6.125 rods, ARP rod bolts, L19's
H11 custom head studs
6.0 MLS head gaskets
1.7 Y/T rockers

-I would run aftermarket rods but thats' me
-I have yet to see a turbo setup that made power to 6800 rpms
-I'd look for less gear see above
-600rwhp, 9:1 compression, ported heads, I'd say 10-12 psi depending on how efficient the combo is

1point3liter

John,

Thanks, it's a fun car. Hopefully I'll have it back together soon.

So you really feel that I'll need heads to make around 600rwhp at 9:1 compression with lets say a t-76 / .96 exhaust? When is hp dropping off rpm wise for the majority of turbo ls1s?

What about people using water/alcohol injection? I would imagine they are able to run more boost safely and make higher numbers without heads.

Got Me SOM

iTrader: (2)

you wont need heads but they'll help make about 40 hp. lets just say it won't hurt to do heads you may want to run arp head studs and o ring the heads for insurance to keep em from lifting.

do a search on rob raymer's car he has run alcohol injection he is pretty much the turbo guy here on this forum. also harlan who has a tt solid roller setup knows a lot too. both guys make power in the 700's

at 600 rear wheel that car should fly and be scarey fast. hope ya got a full cage in that thing.

JZ 97 SS 1500

iTrader: (2)

I would just slap some low compression pistons in and use a T76. Easy setup for 600rwhp or more.

Jose

Pro Stock John

iTrader: (34)

You don't need heads to make 600rwhp.

I have not seen a turbo LS1 stock cube setup make power over 6400 rpms. I think all of them that I have seen have peaked below 6200.

CAT3

iTrader: (9)

There so many ways to do it. Many are right, right?
I would use forged rods, since you want the extra strain of autocross, which stock rods can handle the 600rwhp level, but not for extended periods of time, IMO.
Gearing also, might want to come down if you could. Heads, you could do a set and would require a little less boost.
Interesting project. Good luck.

Pro Stock John

iTrader: (34)

To be ubercheap I would reuse the stock rods.

You will need a significant compression drop to do 600rwhp on pump gas.

Speedfab

My advice for you is this:

Bring us the car, motor, some Bud Light, and a little paper. And don't forget we already need a cage. I'll make that thing faster than you'll ever need to go. Oh yeah - found enough pieces to put together a quality T72 or 76, so that's one part of the puzzle in place.

I too would like to hear from a few more of you guys that have put together GenIII turbo engines, specifically regarding cam selection, valvetrain components, and what kind of bottom end work was done/which parts were used. TIA

Tracy G

1point3liter

lmao... I wasn't exspecting to see you posting here.

I'm motivated. Hopefully it won't take me too long to come up with the funds to piece it together. I'll give you a call tomorrow. Thanks.

1point3liter

I really don't have the money for a set of heads on top of the rest of this project. I could maybe pick up a set in the future, but I'd prefer to wait till the long awaited AFR's are available.

I do currently have a set of ARP head studs. O-ringing may be worth while. I thought most people o-ringed the block not the heads. I could be wrong... I'm used to dealing with rotards.


Hopefully it's scary. I haven't had the car spook me from acceleration in a very long time. Scary is good. Oh yea, and it currently has no cage, roll bar, or harnesses. I think the track officials at gainesville hate me.

1point3liter

I'm finding the same thing the more and more I hunt. 6400-6500 will work.

1point3liter

I'm leaning towards a set of forged rods to accompany the pistons. A little more down time scraping up money may be worth while in the long run.


QUOTE=CAT3]Gearing also, might want to come down if you could. Heads, you could do a set and would require a little less boost.
Interesting project. Good luck.[/QUOTE]

Gear wise... I'll just have to deal with the 3.9's for now. Once I get her up and running I'll just have to drive through it and find a solution later.

1point3liter

So you're thinking more along the lines of 8.5:1 or even lower?

Which pistons would I need for 9:1 with 5.7L heads? Are there pistons available that can lower the compression even lower without 6.0L liters heads?

Thanks again to all of you. This boinger piston stuff is a lot different than the rotard triangle crap I'm used to playing with.