i looked through the FAQ's and also did search w/o success.

i have a question concerning building an exhaust header that is fabricated to take advantage of the divided turbine housing, in my case grouping 1&3 and 2&4 since my firing order is 1432, versus building a 4-1 merge.

does the divided housing really help spool quicker using the split setup vs a merge? can you explain why if it does please?

now, if you do build an exhaust header for the divided housing do you run one huge wastegate or two, one for each half?

the follow up question to that would be, how do you determine which wastegate or wastegates to use, size wise. im going to either get a gt4088r or gt4294r, whats your suggestion.

thank you
dean

 

Sorry to get side tracked..but what ARE your goals? The only reason I ask is this could take alot of concern off your hands being sometime people only want 350whp and think they need a montserous setup.

 

looking at 650hp, drag race only.

2276 cc

8500 max rpm

i just went back and read garretts explanation of divided exhaust housing. just wondering from real world experience.

just trying to make the most efficient setup. i know the gt42 is a tad big but will work as another racer with similar setup has set the record for vw last year using it. boost pressures are prob 35lbs.

hope that helps.

ty
dean

 

Sorry, no personal experience with this. All I can say is people rave about it and the better spool characteristics. Another nice thing is the fact that the split will cut your .ar in half for each set of runners. Also, you get the benefit of running twin 44mm tial wg no boost creep. Sorry I couldn't be any better help.

 

no, that does help, ty

any input is good.

dean

 

I run it, much better response during the spool up and never have any creeping or spiking at all

 

you run two wastegates, they can also be smaller especially if placed well. It has something to do with keeping the exhaust flow smoother i believe, when paired correctly.

 

I'd post this question in the drag racing forum. You'd get better responses with real world data and some extra technical information.

 

would that be legal? lol, i dont want to get into trouble

ty, ill go ahead and do that

 

booo to anybody buying a 42r with plans of only 30psi!!!

 

haha, a stock vw case wont handle much for long, 35 might be max but for short time. aftermarket case is a few grand, plus new crank and flywheel... so it works out to be about 5 grand actually.

i know its in jest but i hear ya.. just plannin for next year. this is costing a pretty penny going efi, new turbo, wastegate, bov, ic, etc etc etc...

 

Yes, with the divided setup you're using kinetic energy to slap the turbine wheel to get it going, instead of building pressure to spin the ex wheel(think short runners/primaries)... with no overlapping exhaust events you'll improve scavenging over a typical 4 into 1 merge...

You can do either one. However, if you use one gate you'll want to place a divider in the middle of the wg merge to block pulse mixing while the gate is shut...

Placement will play a major role in wg size. Try to avoid turning the flow 180 degrees like most of the topmount setups you'll see here on ht... if you run a number of turns to and from the wg plan on using a larger one. Also large gates are good for running low boost on big turbos.

 

id look into the newer billet wheeled turbo's from precision there is an evo that made 850 while still on a t3 turbo and the price would be about the same for a DBB billett wheeled turbo as a gt42r
also look into bullseye power borg warner turbo's as people are having success as good or better than a 42r for the same price or cheaper for both options

a divided setup with the proper sized hotside will spool 700-1000 rpm's sooner than an undivided setup

talk to the shodan on hear and he could really help you out alot and arnold at pag parts is into vw's and he really knows his stuff when it comes to turbo's and turbo sizing as well

just trying to help out a fellow dubber