kk90

I am looking for realistic goals for my 2000 ls1 I have a 67 mm turbo mounted with arp head studs and skat piston and rods. I am wondering how far my stock cam and heads will actually take me.
any information would help thanks

IronBlocked

Do you have long term reliability on your mind?
Depends on whihc 67, but probably 6, 700.

kk90

I do, I am looking to swap out the stock cam and heads. but I would like to be a comfortable 600 at the track and 500 on the street.

JoeNova

Which 67mm turbo is it?

67mm is normally a pretty small turbo, especially for a pistons/rods LS1, unless its something like a Borg Warner which can have a very large turbine for that size compressor.

500 to the wheels with a stock cam is pretty reasonable for a quality 67mm turbo.

kk90

I believe it is a precision 67mm with a 60 ar compressor housing. its not very big.

kk90

once I get all the bugs worked out in this set up I do plan on upgrading the cam and heads as well as the turbo an the fuel pump. I have rather high goals for this car. an I want to do it on the 347 block. an its not really a budget build its a toy so I treat it like one.

Ryans99ls1

iTrader: (16)

click on the build thread in my sig. 67mm is pretty damn small regardless of your hp goal

JoeNova

You can get very very very far without upgrading heads. Cam is a preference, but with the right turbo the stock cam will make considerable power. Once you go with a larger cam, you open up the opportunity for increased backpressure and reversion, as well as increasing the CFM demand of the engine and putting the compressor in a different efficiency zone.

I would stay stock heads and cam for now, and upgrade the turbo. A cam/head upgrade with that turbo is going to be pointless.

Do you have any idea what the A/R is on the turbine or what size the wheel is?

kk90

this is good info. the turbine housing is a .68 A/R it is fairly small. but I am working on spooling issues. I do not have any boost leaks. But my tune is extremely rich an i have yet to put heat tape on my hot side. ( for the record this is a rear mount). but what size do you recommend moving up to? 70mm?

JoeNova

You can get away with less turbine on a rear mount setup, but .68 A/R on the turbine is still tiny. That turbo will probably start to choke around 500-600 whp unless it has a huge turbine wheel.

I would actually recommend the On3 76mm for this. Small turbine wheel, and you can get away without the need for the standard .96 A/R they offer and get something slightly smaller. Its also a small turbo so it would work well with a rear mount.

Otherwise I'd say go with a TC76. Thats probably a good size turbo to start considering a better cam with.

kk90

I have 8:5:1 cr so the car is a puss down low till it hits boost. Thats y I have the smaller turbine housing. But your right once I hit boost it feels like the car is not pulling through the turbo. if feels like a na car pulling the same through out. But i am only running on wg which is 6 lbs. how many pounds do you think I am safe to run with the proper tune? With what your saying makes sense. I feel like it has so so much more there.

kk90

also is that turbo on a T3 or T4 flange. I am running a T3 do you think with the larger turbo I should go to a T4. I am still kind of New to all of this. I am learning as fast and as much as I can.

JoeNova

I think the current record for stock bottom end LS1 is around 800 whp. I'd say with forged pistons and rods and a good tune, you're set for pretty much whatever the block itself can take.

Yes, I'd consider upgrading to a T4 in the future, but for now you could probably get 12 lbs or so out of that turbo before it starts to run out of steam.

kk90

I have been doing some quick reading on here. an reading up on the tc76 which I like what I am seeing number wise. you pretty much convinced me to switch. I have been wanting to for a while but i have so many other things that are messing me up. I put a Th400 in the car an put a TCI 10' converter with 3500 stall. an when I take it out on the street it literally does not see 1lb of boost till 3800rpm. I am looking to get a lower stall. about a 2400-2800 for more street driving. but leaving of the trans brake it will blow the tires clean off. I feel like its not even running right to even get a good grasp on power. the motor is finei nlbelieve its in the converter. what do you think?

JoeNova

3500 is a pretty loose converter for a street turbo setup. Turbos like load. Load creates heat and helps with spool. Even a lot of the 700+ hp guys are running a lot less than 3500 stall.

Your transbrake helps create tons of load as well.

kk90

what stall do you recommend?

kevin87turbot

iTrader: (2)

You definitely need to tighten up that converter several hundred rpm. An 086 stator and a "0" impeller is a good start. You might just call up TCI and get them to do it. Ondra is the man to talk to.

kk90

thanks, this is good stuff. it is def loose to the point where it feels like its in the clutch thy whole time.

JoeNova

Id tighten it up to less than 3000 stall.

Most 1000 hp turbo street cars ive dealt with run 3400 or so stall. With a smaller turbo, and a rear mount to boot, youre looking at 2600-2800 for a decent stall speed.