hi all ...i owned zo6 2003 i just done with my engine 348 :
-Callies crankshaft.
-Callies connecting rods
-Diamond pistons dish for boost
-afr heads 225 72cc

I'm looking for one of those but what i know about it, the best TWIN TURBO KIT is TTI X ??
By the way, I like to do compares between APS and STS ??
-which one you think superior/powerful for street:
650+ hp .
use daily .

thanks..

 

No comparison, the APS is superior.

The STS kits look like a good deal, here is a list of my opinion of them, and why I don't sell them anymore:

1. STS claims that heat is not required to help spool the turbo, that exhaust velocity does the job.
Major retailers of the STS kits sell the kits with exhaust wrap, to help spool the turbo. We have done this at our shop, and it helps quite a bit. It is obvious that the closer to the engine the turbo is mounted, the more efficient it is going to be.

I copied this from the STS website.

"Doesn't heat create the velocity in the exhaust gasses to spool the turbo?
No, heat doesn't create velocity. Heat creates volume. If you look at any of the physics laws for gasses, you will find that pressure and volume and heat are related. PV=NRT is a popular one, The V isn't for velocity, it is for Volume.

The turbine housing is what creates the velocity. The scrolling design that reduces the volume of the exhaust chamber as it scrolls around causes the gasses to have to increase in velocity and pressure to maintain the same flow rate.

Hotter gasses have more volume, thus requiring a higher A/R which in effect means that it starts at say 3" and scrolls down to approximately 1". Lower temperature gasses are denser and have less volume, so they require a lower A/R housing which would start at the same 3" volume, as the turbine housings use standard flanges, and scroll down to say 3/4".

Now if you were to reverse the housings in application, the conventional turbo would spool up extremely quick, at say around 1500 rpm but would cause too much backpressure at higher rpms because the higher volume of gas couldn't squeeze through the 3/4" hole without requiring a lot of pressure to force it through. On the reverse side, the remote mounted turbo with its cooler denser gasses, wouldn't spool up till say around 4000 rpms but once spooled up would make efficient power because it doesn't require hardly any backpressure to push the lower volume of gas through the larger 1" hole."

So I take it the exhaust wrap should not make a difference?

2. You don't want to run catalytic converters with a rear mount turbo. Years ago a guy brought in a Ferrari to us that had a rear mount turbo. One of the catalytic converters internals came apart, as they sometimes do, and parts of it lodged into the turbo, ruining it. I predict that this will be happening to the STS turbo customers.

3. The oil return line is routed into the passenger side oil cap on the STS kits. This line has a habit of coming loose, and spraying oil into the engine compartment. It happened to us, and I have read where it has happened to other people.
These engines already have enough oil returning down through the heads, they don't need more! This is a bad design, and many people are rerouting the oil return line to the oil pan, where it should be in the first place. The problem with running the line to the pan is now you have to drill or punch a hole into the oil pan to run the oil line, unless you remove the oil pan. We recently removed the oil pan on a customer's car, and welded a bung into the pan for the oil return line.

4. The turbo hangs without brackets supporting it, and will sag over time. We add a bracket when we install these kits, I don't link seeing the turbo dangling there.

5. The air filter is in a bad location, as is susceptible to dust, water, dirt, etc. STS offers a cover that goes over the filter, but we found the cover seriously hinders performance. We proved that on our chassis dyno.

6. On the F Body STS kit, a driver side subframe connector cannot be used. STS claims their plumbing that is routed down the driver side does the job of a subframe connector. We find that humorous, at best!

7. The plumbing underneath the car hangs too low in my opinion, and you don't want a lowered car with an STS kit on it.

8. The silicone couplers that are provided with an STS front mount intercooler are thin, and we had two of them blow apart. The intercooler plumbing that was provided with the front mount intercooler option that we ordered for a customer's car was poorly routed, we ended up using our tubing from our front mount kits that we sell.

9. The oil lines sure have a long way to run, from the front to the rear, and back up front. If a leak developed, it could be a quick way to ruin an engine.

10. It would be relatively easy for someone to slide underneath the rear of an STS equipped car, and steal someones turbo.

11. The boost line running back up to the engine from the turbo has silicone couplers at various points along the way, and can blow apart.

12. Any exhaust leaks will diminish the efficiency of a rear mount turbo.

Hopefully this helps. Bob

 

guess the sts sucks ......

 

There is now a better alternative, now that APS has a kit out. Bob

 

both the aps and TTI kits are great. You can even get the PTK copy off e bay for the hotside and intercooler and save a couple thousand dollars, you just gotta buy quality turbos for that kit and some other things.

 

exhaust leaks hinder performance in any turbo car not only STS cars....... Werent you toting STS kits a while ago to be very good.....

Also in point 11 you say that it has couplers that can blow...... every turbo kit i have seen have them........ they break on procharger cars and front mount turbo cars just as quick as they break on rearmount cars.

I have seen oil lines break on conventionally mounted turbos many times. the sts kits i have delt with in my area have had no problems. Im sure you see many more though but i have never heard of them having an oil problem (my truck, buddies GTO, brothers silverado, another buddies camaro.)


I do agree with you on that heat has alot to do with spool time as heat = energy and energy = spool.

With the filter set-ups, when i look @ the APS website on the f-body kit those filters arent much higher if any then the STS kit if any...... they sit right behind the lowest part of the front bumper..... same with some of the procharger install pictures i have seen.

Not trying to call you out or start an argument, just that you seem to really come down hard on the STS kits and act as if other F/I applications have no faults. I love my custom rearmount. Might not be much to yall but i am much faster then any of my front mount turbo counterparts. closest one has cam, full MPFI conversion, and a bigger front mount turbo then me and i still trap better then him and E.T. better then him.... Never taken the valve covers off my truck.

 

the original poster asked for opinions on the two kits...Bob offered his opinion, doesnt sound like he was comin down on the kit. in his opinion, APS would be a better way to go.

and your right, the APS filters dont appears to be any higher up than the STS however, they are covered up pretty well from the elements and the STS is not.

 

i would go for the LPE TT i have it on my car and absolutely love it
i know it is not a kit and LPE dose not sell it as so but as i know the APS is basically a copy of it

so my vote goes to APS
good luck

 

I have an STS on my GTO, and share a few of the same concerns that Bob enumerated above.

I have a GT76 that weighs enough to have my system sagging, and I need to have a better hanger system installed to get it back up where it needs to be.

I had to have larger piping fabricated and get a larger IC due to STS shipping standard size piping and IC with my "spec'd" GT76 kit...which was insufficient to support my 408/GT76. To their credit, they provided the larger IC at no cost. However, we provided them with all specs for my GTO, and were delivered standard kit with a larger turbo...definitely NO engineering was done for my specific system.

I also did not like the oil return and instead plumbed the return line into the rear of the valley cover. I have not experienced any issue with this location as opposed to the oil pan, however I also have room for this location due to running a Victor Jr intake.

The location of the air filter is not best for extremely dirty or wet areas, but I do not live nor drive in either of these so it has not been an issue for me. I will say that the APS air intake location would be better, even if at the same install height, simply due to the fact that it is AHEAD of the tire/roadway interface which is where dirt/water is disturbed and becomes airborne (when not following behind another vehicle that is doing that for you...).

I cannot speak to the spool time as I have only had a rear-mount on this vehicle, but will be dynoing separately with the STS std piping (figures in hand), custom uncoated/unwrapped 3" mild steel hotside/3" alum cold side, coated/unwrapped hot/cold, then finally wrapped hotside only. This should give me some very definitive empirical results (temp/baro not withstanding) of the benefits of coating & wrapping with regard to spooling effect.

In retrospect, had the APS kits been available when I embarked on my turbo journey, I would have gone that route, and actually saved quite a bit of money over my "spec'd STS kit".

Again, the above is my experience and opinion.

 

sound good for APS kit ,but could any one of you guys tell me where can i get a good deal & price for APS kit ??

 

from APS themselves.... www.airpowersystems.com

 

peter@airpowersystems.com
here ya go dude .. good luck

 

Those guys at exotic performance plus really knwo what there doing. every car ive seen out of there is incredible. I deffinately trust there opinions. have never been a fan of the sts kit but never owning it , i never htought it was right to talk bad about it. Bob makes alot of great points through there expiriences with it.

 

Here's a link to the APS C5 twin turbo system web pages and feel welcome to pm me at any time if you need any other info, happy to help out where I can.

Peter

http://www.airpowersystems.com/corvette/c5.htm

 

thanks peter every thing cool.

 

Out of those two kits I think the APS is vastly superior. You'll make more power under the curve (where it matters) and have a better exhaust selection.

 

Most welcome and let me know if you have any questions.

Peter

 

I have never had an APS system. But everything I have seen or heard is positive. APS gets my vote. Plus APS is involved with the forum. I do not see STS posting.

 

TTIX is far more proven on the c5s than APS. Been around longer and run by a lot of the FI guys on corvetteforum.

APS is still very new, so time will tell. So far, so good.

Both are quality kits.

 

the APS can have troble making as much power as the TTiX stuff. i think APS use smaller turbos. still a very nice kit. just need APS to get the turbo from the Z06 to fit!

Thanks Chris.