Some thoughts I couldn't find answered.


STS kit on our trucks,
1) ASP underdrive pulley- does it matter
2) Are headers not recomended and Would jet hot coating the factory exhaust manifolds help or hurt considering they keep the heat in the exhaust.
3) I have read that 3.73 prolly would be more benifical than 4.10 to give the Turbo time to spool up?
4) does the reverse cam profile pertain to the rear mounted turbo or does it adversly matter with a medium cam such as the ever common 212/218 114+4, or 115 split.
5)As far as a catback were exactly does the kit end. On say- a signal magnaflow 3" I'm assuming if you wanted to retain the muffler it would have to be moved back closer to the axle?


I still like the Radix but was wondering.

 

Creederado~ I dont know about 2-4 but I think that ? 1= it doesnt matter and i know for ? 5 i will not be running a muffler at all. F8L could probibly give you some good ansewers.

 

you don't use headers with a turbo, you use manifolds that come with the kit I'm pretty sure.

I don't see why gears would make a difference, STS is supposed to spool fast because of the rear mount design, cooler (denser) air spins the turbo easier.


don't know about the cam thing.

I've been convinced many times to go with the radix over the STS, its just a better, more complete system. and you get a drivetrain warranty.

 

STS kit on our trucks,
1) ASP underdrive pulley- does it matter --
NO

2) Are headers not recomended and Would jet hot coating the factory exhaust manifolds help or hurt considering they keep the heat in the exhaust.
The benifit of headers is not the same as it would be without turbo..

3) I have read that 3.73 prolly would be more benifical than 4.10 to give the Turbo time to spool up?
RPM's are what will spool the turbo's, their kit is very well matched and has little lag.. But in answer to your question I would think exactly the opposite.

4) does the reverse cam profile pertain to the rear mounted turbo or does it adversly matter with a medium cam such as the ever common 212/218 114+4, or 115 split.
Reverse cam profile will help spool the turbo's faster no matter where they are mounted.

5)As far as a catback were exactly does the kit end. On say- a signal magnaflow 3" I'm assuming if you wanted to retain the muffler it would have to be moved back closer to the axle?
You probably wont want to run a muffler or if you do a much smaller one. The turbo will quiet your exhaust quit a bit, especially if you retain your cats.

I still like the Radix but was wondering.
Boy, this one is always a fun one on here. My philosophy is that Turbo is free horsepower superchargers aren't

 

I'll take a shot for ya mate.


STS kit on our trucks,
1) ASP underdrive pulley- does it matter

I would reason that yes it could make a difference as your gains have nothing to do with the turbo. Would I spend the money on it? Probably not since it's so easy to gain the extra 10rwhp with a turbo.

2) Are headers not recomended and Would jet hot coating the factory exhaust manifolds help or hurt considering they keep the heat in the exhaust.

Headers do not seem to make much difference at all. Even the Hemi guys are seeing these results. IMO I would stick to the sotckers for sealing reasons alone. Aftermarket manifolds/headers will almost always leak worse than stckers. You NEVER wants exhaust leaks with a turbo setup. They retain heat better which is good, keep you smog compliant also. I am gonna have my stock exahust pipes coated from the maifolds back to retain heat for better spooling on my larger than normal turbo. (.96 A/R on GT67 or GT70).

3) I have read that 3.73 prolly would be more benifical than 4.10 to give the Turbo time to spool up?

Turbos love load. The more load the better the spool to an extent. You wanna match your gearing up for your expected 1/4mph RPM but you also don't want a low gear set like you would for anyother poweradder. Turbos are weird that way. Most F-body guys like to stay in the 3.23-3.42 range on mild setups. It is much harder to spool up a turbo with a 4.10gear than it is with a 3.42. Once of the guys at Synergy is going to change his 4.10s for 3.42s for that reason alone.

4) does the reverse cam profile pertain to the rear mounted turbo or does it adversly matter with a medium cam such as the ever common 212/218 114+4, or 115 split.

I'm not a cam guy so I can't answer for certain but the reverse split is not specific to STS. It is a typical cam style for turbos since they work differently than Superchargers or nitrous where you want a lil more emphasis on exhaust durration. I've seen people use less than optimal cams and still have good results. Just ensure that you don't have a ton of overlap and you'll be fine. Otherwise you'll be losing out on potential HP by allowing your high overlap cam bleed off boost.

5)As far as a catback were exactly does the kit end. On say- a signal magnaflow 3" I'm assuming if you wanted to retain the muffler it would have to be moved back closer to the axle?
On my setup I have about 2' of pipe coming out of the turbo. From there I welded on a 3-bolt flange with a short piece of pipe to a 20" (or so) Magnaflow, another tiny piece of pipe with a turndown to dump it RIGHT behind my bumper. Only drawback is a get a lil carbon on my rear bumper now in a small spot. In otherwords there is plenty of room to add a small muffler.

 

Just a side note and a bump for ya James...

I saw an STS regular cab at Gainesville Saturday. Standard kit, 5-6 psi, was running 14.1's @ 97-98 all day on stock tires. He couldn't really brake stall the truck, so it seemed kind of laggy to me, but man it really screamed when it got into boost.

I just don't see how anyone with more than a 2/4 drop could run one.

BTW James, I concur w/ F8L on the gearing...you'll need a numerically lower gear for a turbo setup. I would think 3.42's would be good.

 

chris99gmc installed his with a 3/6 drop

 

Hmmmmm, I understand what you are saying here F8L Z71, I am just having a hard time understanding it.. I know it seems to be the consensus... I guess its one of those things that is just hard for an old schooler to comprehend.. I can understand if you are running out of gear, or maybe without any stall.. Or maybe in a car, but I just cant see it in a truck, Oh well I guess I am just narrow minded..

 

Flipper, you're looking at RPM spooling the turbo which is not really the case.

The turbo has enough exhaust gasses around 3000-3500rpm to turn the turbine so getting to 6k RPM as quickly as possible is not needed. In the case of a turbo you want to create a load. By doing a higher gear (numerically lower) you acomplish this. The extra efficiency of the turbo makes up for the lack of gearing.

I believe almost all the GN guys stick with 3.42s and a 28" tall tire.

 

Yeah, and he also has 22s. Most peole with a 3/5 or 4/6 are running 18s or 20s. There's no way that piping would even come close to working on my truck.

After looking at the kit up close Saturday, it really made me think twice about the kit!