Twin Charged, Compound boost with BW S475 Turbo and TVS 1900 Blower

[kbracing96]

I bought a used 38mm Turbosmart from a buddy, that is gonna go in crossover pipe WITH priority over flow. Gonna go on the outside of the bend where the pipe makes the turn up to the back of the manifold. Should be able to control the boost better with both WG's hooked up. I also got a sweet boost controller coming too .ProParts - Gauge Controllers, Mounting Pods I've just been driving it as is and watching the boost gauge so i don't over boost it. Its drivable at WOT till about the top of 2nd gear. I got to go play farmer for a buddy for about 3 weeks, so won't have time to work on it for a while.

[CHEVROLADE]

damm,cool man.i bet you just want to keep it gunned all the way lol

[bangbangskeetskeet]

Pretty darn cool guage man. When will you be totally done with it?

[kbracing96]

damm,cool man.i bet you just want to keep it gunned all the way lol

Haha, ya. Feels REALLY good when it shifts from 1st to 2nd and jumps from 10 to 15 psi at the same time, lol.

Pretty darn cool guage man. When will you be totally done with it?

Done??? Never! that means i would have to die! lol.

[farmtruc]

I've been studying other compound turbo setups and I think I might have figured something out for you.

Maybe the over boosting is caused by the compounding effect of the turbo producing too much boost and not controlling it before the tvs.

SO, what about putting a wastegate between the turbocharger and tvs?

[kbracing96]

I've been studying other compound turbo setups and I think I might have figured something out for you.

Maybe the over boosting is caused by the compounding effect of the turbo producing too much boost and not controlling it before the tvs.

SO, what about putting a wastegate between the turbocharger and tvs?

Well, with the WG being referenced after the blower, it "should" be opening when X boost is reached in the manifold and maintaining it there. I think the underlying problem is there just isn't enough back pressure pre-turbo for the WG to work effectively. I think increasing the size/quantity will help in dumping the large amount of volume at a relatively low pressure. I'm trying to work a deal right now to get some electronic pressures senders so I can see what kind of pre-blower, post blower and back pressures I have and log them with EFIlive.

[kbracing96]

Well, I haven't been messing with it too much latley, but I did try a bigger superchager pulley. I put a 3.6 on it which makes about 4 psi until the turbo spools. I put a new boost controller on it, and have it set to 10 psi, so now I have 2 boost gauges so I can see the manifold boost and the turbo only boost.

From a standing stomp, it jumps up to the 4 psi the blower makes and then spools the turbo pretty fast and maintains about 5-6 psi over the turbo only boost till about 10psi and 4000 rpm, then the boost just starts climbing like a procharger. I've seen 20psi 3 or 4 times! .

I know it still need more waste gate, but it just doesn't feel like 15-18 psi should on this motor and the money tree has pretty much dried up on this science project so the Blower is coming off in the next couple weeks (and is for sale ) and am gonna go back to turbo only with this S475 and a quick spool valve to get it spooled. One day, when I have a little more dedicated play truck, I will most likely revisit this experiment.

[Trick1]

whimp. maybe it will stop at 20psi. lol PM me what you want for a that heavily used 1900.

[kbracing96]

Ok, I got a second WG in the crossover (38mm), where the first one (50mm) originally was. Boost is now in control holding about 10 psi. Gauges are showing that with this 4 psi pulley, it's hitting the initial 4 psi, then the turbo spools up and carries it on up to 10psi which is the 38mm WG spring pressure, the 50mm gate has about a 6psi spring in it. Seem the blower is making about 5 psi and the turbo is making the other 5 PSI.

Having the OTHER problem now, can't get the boost controller to turn UP the boost, lol. Checked it out today and the controller is doing what it is supposed to be doing, so must be some kind of WG problem... Gonna put the 7psi pulley back on it and keep playing with it, I'd like to get it so it will hold a steady 15 psi. If I can do that I'll try and take it to the next track day which is a week from Sat unless some one buys the blower befor then .

It was nice to finally be about to make a nice long pull with it with out having to lift off the throttle toward the top of 2nd gear. Tune looks good at 10 psi, 11.5 afr, 20.5 timing (no KR) and IAT's in the 105-110* area with 85* ambient. Scangauge performance meter says, 13.4@105 on 10psi, but who knows just how accurate that is.




Got my quick spool valve for when I go back all turbo the other day, looks VERY nice!



Blower is officially for sale, Magnacharger TVS1900 Truck Kit - PerformanceTrucks.net Forums

[kbracing96]

So I did a little playing this afternoon. Hooked up my second boost gauge to read exhaust back pressure before the turbo. Made some runs still with the 4psi pulley (3.6") on it, making about 10 psi of boost and back pressure would go up to about 8psi at 4000 and slowly creep up to 10 at 6000, then drop back down at the shifts. IAT's start around 105* where they normal are and would clime to about 125-130* buy about a 100mph. They recovered very fast though. Back down to 105* with 2-3 minutes. Check the water temp with my hand and was luke warm.

So then I went back home and swapped the 7psi (3.3") blower pulley back on it. Made the same 10 psi boost and peak back pressure, but had a lot more punch out of the hole. I can't seem to turn up the boost any with the boost controller, I think I need to put a stiffer spring back in the WG now. I have the softest spring that comes with the synapse WG kit in it (about a 4psi i think) and no pre-load spring. I made about 4 back to back pulls and by the last one, the IATS at the end of the last run were pushing about 154*. Drove the truck around for about 8-10 minutes and they where back down to the 105-108* range which is pretty much where they run all the time unless it's pretty cold outside. Ambient was in the upper 80's during all this time. Just a little R&D for ya guys.