parallel turbos?

[drunk on diesel]

most gas setups have cylinder heads that flow and don't run 40-60psi of boost.

they might make 800hp at 15psi

compressor map compressor map compressor map compressor map compressor map

 

[Magnum PD]

Any good links for compressor map info?

 

[superpsd]

Sequential setups are not compound setups. They usually use a smaller turbo for low end response then a gated system lets a larger turbo charger come on line as exhaust volume increased to be able to push a larger turbo. Some years of the Supra I think came like this.

I have seen some gasser setups where only the compressors were compounded. Most gassers however do not use 80 psi. Most street gassers are pushing 20-30 psi and that's about it. Higher PR and your usually talking drag only cars.

Compounds are how you can achieve high pressure ratios as the boost is not added when compounded its multiplied with multiple variables.

 

[Wes Lewis]

Parallel turbos are more for top end, little harder to spool but can move a lot of air once they are lit. Common in gas engines because they run smaller turbos, then gate them on the top end, and have a lot of air flow over a wide rpm range.

 

[drunk on diesel]

common in gas engines that are V configuration because they're easier to package than a large single

 

[superpsd]

It all comes down to the turbocharger specs. CFM for CFM smaller twin turbos versus a larger single will spool quicker and have more street manners. The single will be laggy but pull harder up top due to less exhaust restriction. Turbine housing sizes play a huge part of the balance. Smaller housing as in the smaller ratio bottleneck will create faster response with reduced higher rpm power due to higher backpressure. A larger housing will be laggy at lower flow and great at full tilt as the exhaust restriction has been reduced. I have simply taken the turbine housings on a few of my builds and ported the housings to increase high rpm power at the expense of a little low end response.

There are other things that can improve response however. Ball bearing turbos, spool valves, nitrous, ceramic coatings to keep the exhaust temps contained in the hotside (hotter exhaust gases move at higher velocity) and more.

 

[tangoparson]

Any good links for compressor map info?

Garrett has a fantastic tutorial on their website.


Sent from my cheyenne mountain when the NSA wasn't looking.

 

[97stoker350]

Wicked wheels come stock on obs turbos btw

 

[thatsmokinobs]

I had thought they were basically the same, but I wasn't sure.

 

[thatsmokinobs]

So what I'm getting from this, is that parallel turbos are similar to 2 pumps on a hydraulic system. With one pump, you'll produce 2000 psi and say, 20 gpm, and with 2 pumps, you still make 2000 psi but 40 gpm. So with one turbo, 20 psi and X CFM, and two turbos, 20 psi and roughly 2X CFM, correct? So it would be more for high performance/ high rpm applications vs street driven?

 

[drunk on diesel]

pretty much... like a LOT of RPM

or a lot of cylinder head flow

 

[thatsmokinobs]

So ported/polished the f*** out or even custom heads to make it streetable-ish? Sounds fun lol

 

[97stoker350]

Itl drive no matter what setup u put on it but what they are getting at is its just mo ey and time down the drain when a 468-75 will do everything heui could ever hope to accomplish... On a street truck

 

[thatsmokinobs]

Yeah I understand. It was just a "what if" type thing. Just was curious how well it could work.

 

[drunk on diesel]

here's the thing... you can actually figure out if it's going to work if you have cylinder head flow data, projected horsepower levels, and know how to read a compressor map.

no one is going to spend the time to do the research on your daydream, unfortunately.

2nd best bet is to mimic a combination that someone else has used that has worked well. Most people who have put together successful combos haven't wasted their time with parallel turbos. As such, you probably won't find a proven parallel turbo combo to mimic. I've certainly never seen one under the hood of a Ford, Dodge, or GM diesel pickup, and I've been doing this diesel **** for almost 20yrs.

I've also never attempted it because I try not to waste time and money

 

[Cutting-Edge Diesel]

There are several parallel turbo set ups In prostock diesels. But they also rely on nitrous.

 

[Bustedknuckles]

Confederate diesel had parallel EFR's on their 6.7 for awhile, went back to a big single though.

 

[drunk on diesel]

There are several parallel turbo set ups In prostock diesels. But they also rely on nitrous.

if I were looking to mimic a pro-stock level combo, I might consider it...

Confederate diesel had parallel EFR's on their 6.7 for awhile, went back to a big single though.

I would not mimic anything Confounded diesel does

 

[Cutting-Edge Diesel]

if I were looking to mimic a pro-stock level combo, I might consider it...

Would like to add that I'm with you. Wouldn't even think about it on a street truck. And Im building a Prostock car and it has compounds.

 

[drunk on diesel]

Im building a Prostock car and it has compounds.

very sensible approach considering your desired power levels and your cylinder head limitations (though I realize that YOUR heads are far less limited than the OP's! :drool: )