Alright, someone tell me if this has been posted already, as I don't frequent here as much as I used to.

Okay, so not to start a war again, but ...

Arguments have been made for and against the STS kit and how it is not efficient to run the exhaust all the way back there. Now there is some logic to that, I must agree. However, a turbo is a turbo, and it's still going to produce boost, and I believe the housing is small so that it spools well. So the fastest boosted LS1 of last year, Ronnie Duke's drop top Trans Am went 8.52. Now if you look at the pictures and read the description, Ronnie Duke sent the ol' intake back to the aftercooler to the back of his car. Then brought it back to the front into the intake. Hmm, sounds kinda like a turbo kit I know of... Obviously he loses boost pressure from doing so, but he's still running 21 lbs of boost.

Just making a case for the STS... I want more FMIC pics!!!

Yell at me if I'm wrong.

 

Speak of haters, I spoke to a very well known tuner today and we talked about my combo that I'm putting together. I told him I'm going with an STS style intercooled T70 (when ever it gets here) with a .68 AR housing and 42lb injectors with a 340 intake pump. This is in conjunction to the mild H/C and 3500SY that I already have. He says through my A4 on his Mustang dyno I'd be lucky to hit 400 RHWP at 8-10 psi. I realize that the Mustangs are far more acurate because they put a true load on the rear tires but man, thats pretty sad I thought, and he says this would be at best! So I ask him how much he "thinks" I might be putting out now, he replies I'm not sure of your combo but probably in the neighborhood of 330-340, so basically he thinks all my time and effort on this is going to be worth a paltry 60-70 hp. Any thoughts, maybe he's right? Oh yeah, he also explained how ineffecient the STS system is because of lack of heat and length of tubing. I'm not saying he isn't right but 60-70 hp just sounds a little weak.
Wolfee

 

Are you in a truck or a car?

400rwhp BARELY on 10psi??? You've got to be kidding me. What an idiot. Maybe he should do a lil more research before he opens his mouth.

There are more than enough people making 410-450rwhp on 5psi to satisfy that argument. Hell I made 365rwhp on 6psi on a 5.3L truck motor that only puts out 225-240rwhp stock.

I swear some people get so stuck on one concept that they can't open their minds to something new.

 

If stock cars are hitting over 400rwhp with 5psi on the STS kit then i dont see how any respectable tuner would only estimate 400rwhp with 8-10psi and a H/C combo....just some food for thought.

 

I know, I thought it was kind of ridiculous because it's a little closed minded but hey, he does have a mustang dyno compared to a dynojet Does anyone have any direct comparisons from the dynojet to the mustang type? I really don't care to take my car to this guy any longer though. Does anyone know of one that could tune me in the western part of OH or IN or ??? Thanks for any help.
Scott

 

I'm saving my money, the STS will be my next mod, along with injectors, and eventually low compression heads/cam/nitrous if my dad doesn't take the car back before hand...

 

Rick was supposed to get me some compressor maps a LONG time ago for the different turbo's he uses. Still haven't seen nor received a copy of them.

The only way you are going to see how efficient the turbo is, is through the compressor map. It's the effect on the efficiency when you change the A/R as drastically as STS has done for their kits to help curb outrageous lag.

I think the big problem when these kits first came out was the claim that a T70 (for instance) on an STS will be just as efficient and make just as much power as it would on a conventionally mounted T70. Without the maps, it's a little hard to say with any certainty.

If anyone has the compressor maps of the turbo's that STS is using, please post 'em up so they can be compared.

 

I believe that verything I've read says that the T67 is used for the LS1 by the STS kit and there are maps available in Garrett's catalog as well as other places on the web.

I don't think the compressor on the turbo cares if it is in the rear of the car or on the engine, and the map is for the compressor, not the turbine.

If anything, the compressor would be more effiicient mounted in the back of the car with less heat coming through the bearing housing from the turbine and heating the compressor airflow.

A back of the evelope calculation will tell you that to fill the inlet tube from the compressor to the throttle plate only takes in the tenths of a second at 3000 RPM (where you would like boost to be in, usually) and is at best a second order effect compared to the inertia of the rotating wheels/shaft and the characteristics of the turbine.

STS says in their website that the temp going into the turbine is about 300 degrees less that it would be if it were mounted at the discharge of the engine manifold. The mass flow is the same no matter where the turbine is, but the gas velocity will be a little greater and the temp will be down for a rear mount turbo. Another back of the envelop calculation will tell you that the energy in the gas flow from the 300F temp drop is in the neigborhood of 15-20%, just about the same as the decrease in A/R ratio that STS supplies in their kit over what the normal area ratio would be. It appears to me that they are back pressuring the engine to get the velocity up into the turbine so the same amount of energy is there to drive the compressor. The only thing I would be concerned about is that the backpressure on the engine might be a little bit higher than for a turbo mounted closer to the engine.

Just my 2 cents...........

 

honestly do you know what your talking about cause im not sure.

first off the main Ineffincy isnt intake air traveling all that direction, though it is a small one. IT is the exhaust gases loosing all that heat/engergy traveling back there. when you loose the engergy and velocity through the distance, performance will go down, and not just in spool time.
Having a smaller AR housing to compensate for this will also kill the power uptop, as the power band dies off easier. its not rocket science, just common sense.
Dukes set up is super charged, not sure why you are comparing the two? sure the intake travels a bit far, but thats not the main issue of the rear mount kit.

sure the sts kits work, but there not as efficiant as one close to the heat source.

 

There is a difference. Dukes car was a blower car which is RPM dependent on boost, not load dependent. There is no "spooling" of a supercharged car. There will be a certain amount of pressure loss going to the rear of the car depending on the bends and the design of the intercooler system. This however is totally unrelated to a turbo setup as far as spool time as the blower is spun off the motor.

That being said I think the STS kit is a very interesting concept. I can't wait to see the bigger engine/boost combos tested and on the road.

 

i wouldnt get it haha

 

Wow , I haven't had time to get on the boards lately since we have been busy tracking turbos down thanks to hurricane Frances...hehe, but a customer e-mailed me this link. And I can't believe how far off some poeple are with these STS setups. I have said this MANY times, the compressor maps are made under SAE J1826 standards. This means the maps are derived using 1100 degree incoming air in the turbine side. The STS systems are WELL short of producing that temp at the inlet, so that is why the lag is so bad even with a smaller 67mm unit on a large 346ci motor. Reading a compressor map for an STS type setup will be just about useless since the map will have to be shifted well to the left. I will hopefully soon show this, as we are working on a turbo testing facility.

Jose

 

I am still looking for someone to post the big changes in 1/4 mile times or even MPH if they are not hooking. The only real fast LS1 STS car is also hitting it with at least 100 shot of nitrous. You can call me a hater, but I am still waiting for some proof. I am puttng a lot of faith in Blackbird to get us some good data on the kit. You rag on people who doubt this kit will work, but you have no real data to support it either. I've seen more data that shows slight gains than shows big ones.

Has anyone measured the preturbo pressure in the exhaust on this kit? I remember one of the first guys who had one blew an exhaust gasket after a few weeks. If we knew pre and post turbo boost we could look it up on the map to see where they are.

-Geoff

 

I'm glad you replied. I started reading this thread and had to close it. It doesn't matter how many times we explain the cons of a STS kit to the lstards, they still don't get it.

 

Just thought it was an interesting comparison, sorry for being a "lstard"

Any way, to each his own, if you wanted to mount your turbo in your ***, it might work, but you're still going to have "haters."

I was simply providing a comparison, and the fact is, with Duke's setup, all that air has to travel all the way back to the back of his car and then all the way back up. Regardless of boost vs. rpm or boost vs. load, the compressed air has to travel a hell of a way. In relation to the STS, obviously the exhaust side is going to be different because, wait, this is earth shattering, turbos run off of your exhaust gases!!!

I was simply stating that if he had put his aftercooler in the passenger seat or even closer... under the passenger dash??? the compressed air would not have to travel as far and therefore not lose much compression. It's almost the same with the STS kit, the inlet has to travel all the way back up the car... losing compression!

Just a comparison, not an apples to apples comparison, sorry I didn't please the LS1tech gods...

 

Abidar,
First, I have no opinion on the STS kits.Time will tell either way.
But Ronnie Dukes intercooler setup is nothing out of the ordinary. MANY turbo and some supercharged cars run the liquid/air charge coolers inside the car. It's pretty much common practice now on the race cars.

The charge air or compressed air piping on the STS kit is not the big issue some guys have with the kit.
It's the exhaust pipe length, the exhaust heat and velocity used to drive the turbine that is the issue. Not compressor pipe length.
Steve

 

They are trying to help by pointing out that you're looking at the wrong end of the stick.

 

good point... I do know it's common practice now, I'll just shut up, go back to and realize that i've been

 

I think people worried abou efficiency should go buy civics, lsx engines are not as "efficient" as your b18.

they make less hp and much less torque, but its "efficient hp".

 

The lack of efficiency in a rear mount kit is a mirror of its potential. The kit is cheaper and can make over 400rwhp; no one is denying that. If you want to make more than 4XX rwhp it's lacking potential and another kit would be better suited. You're comment is definitely the most ignorant to date.