Turbine housing sizing + quickspool valve

[Driver_10]

For the record on my .63 AR T3 turbine with the 60-1 compressor it spooled off idle. It was full boost 1/2 throttle accross an intersection.

I have a 3 spd. automatic TH350 though. 4500 stall.

My .69 A.R t3 non-divided "S256" was about the same way. It did very well on my old 3400 swap and had a torque band like an SBC.

However, a moderately sized housing is restrictive at high rpms. To free up some power at higher rpms requires a larger turbine housing.

The challenge is to create an efficient system with usable low-end torque and good, flat, "mid to top range" power band. The parrasitic losses should as reduced as posible.

(Its a difficult goal, but not an impossible one)

[Mars]

For the record on my .63 AR T3 turbine with the 60-1 compressor it spooled off idle. It was full boost 1/2 throttle accross an intersection.

I have a 3 spd. automatic TH350 though. 4500 stall.

[Driver_10]

Heres a good pic that shows kinda how I intend to run the two wastegates on the "divided pulse" primary set-up...

This is not my pic BTW... but you get the picture

[Driver_10]

basically at low engine speeds the plate is closed, forcing all the exhaust gas through the single, smaller opening, basically changing the turbo into a small turbine A/R, which spools the turbo very quickly, then as the engine speed increases the valve opens, allowing it to act like a large A/R housing, allowing for more flow and power than a smaller housing would.

(You beat me to the punch.) Yep...Thats the theory.
The real benifit of the "quick-spool" valve is being able to use an overall larger exhaust housing which would reduce breathing effort and free up hp.

However, Im changing my approach and using a fairly large exhaust housing in combination with a "divided pulse" style set of turbo headers with dual wastegates. The "divided pulse" system is ultimately more efficient and should provide better boost control. I just wont be able to run nearly as large an exhaust housing as I would with a "QS"-valve and non-divided turbo headers.

[RedBird]

basically at low engine speeds the plate is closed, forcing all the exhaust gas through the single, smaller opening, basically changing the turbo into a small turbine A/R, which spools the turbo very quickly, then as the engine speed increases the valve opens, allowing it to act like a large A/R housing, allowing for more flow and power than a smaller housing would.

[Jonpro03]

I'm still having a hard time understanding how the quickspool valve is beneficial or how it even works.

[Driver_10]

Technically, this turbo will flow enough air to produce 650-700 whp. However, its the flow efficiency and curve, more so than the HP potential that really grabbed my attention with this particular compressor. (Ill only be running about 15lbs. Thats 500rwhp or so worth of air)

I had originally planned on using the Garrett GT3582R which was perfectly suited for rpm and flow of the 3500. (especially the superb surge limit). It blew the specs on my Borgwarner/schwitzer S256 out of the water. "The GT35 was a no-brainer"

The CompTurbo GT35 clone was less expensive than garrett and used the same fittings. After talking to the dealer, he gave me a special bargain on the triple-BB housing and billet wheel. He even included the CNC work for the compressor porting and tig-welded the V-band fitting on the exhaust housing for free.

I paid $1450 total for the whole, "custom built" package. The only final compromise that I made was on the turbine housing. The divided, 1.15 T3 was no longer available, so I ordered the 1.00 A.R. exhaust housing instead (no biggie).

Next is the matter of purchasing the dual wastegates for the new "divided pulse" design.

[2.8-350TBI]

Holy crap, so far the biggest turbo ive seen to be used on a '60 so far...

Great job driver, great job!

[Driver_10]

Well, the new turbo just arrived. CNC cut "anti-surge" housing, billet CNC 62mm wheel, cast aluminum oil/water cooled center cartrige (Its gonna be fun) Ill be experimenting with dual wastegates (one from each runner of the divided turbine). The philosophy is to prevent the pulses from interfering with one-another and maintain high turbine efficiency. Well see how it works.









Heres a pic side by side with my old T3 S256 (which was a great turbo BTW, just not up to snuff for the new motor) Note the difference in exhaust housing sizes (S256 .69 A.R. CT-62 1.00 A.R.)






The old S256 has a buyer now and will find a new home under the hood of 1.8l turbo volkwagon.

[Driver_10]

damn that thing might be laggy for city/cruising fun. that looks like a sick turbo

This is just thier demo unit. My turbo hasnt arrived yet. Im using a billet 62mm wheel compressor combo w/ t3 divided housing and a pulse divided turbo-system. If John could get away with using a Holset HX35 on bimmer 2.5l and spool-up by 2500rpms, then Im sure that I could use a 1.15 a.r. t3. and have full boost by at least 3000 rpms.

[MidnightriderZ24]

damn that thing might be laggy for city/cruising fun. that looks like a sick turbo

[Driver_10]

Now mind you, this isnt MY turbo (Still being custom made) This is the demo unit that they had at turbochargers.com. You can see the aluminum center-section cartridge. Its rediculously light-weight.




Im having my turbo built to the following specs.

Polished, to4-s style "drill-ported" antisurge housing w 4 inch inlet and 2 outlet.
Triple ball-bearing, water/oil-cooled, cast aluminum centersection
CNC billet 62mm wheel
divided t3, 1.15 a.r. turbine w/ 3inch v-band outlet

[Driver_10]

Hmmm.... Dunno why that just sounds wrong..... LMAO!

[RedZMonte]

John,
Ben sent me a rod and I picked up a set of bearings to verify tang location.

Hmmm.... Dunno why that just sounds wrong..... LMAO!

[Driver_10]

Good deal. John, can you believe this is finally coming to a close? I know you should have a very fast/reliable setup this time (as long as another Ike flood doesn;t hit TX )

Ack! Dont jinx me! We still got one more month before hurricane season is over for us. Oh yeah! Be sure and take pics of the PS bracket when it comes back from the water jet. (For my scrap-book, ya'know)