Engine/Transmission (1994 - 1998) 16cm2 turbo housing question

[FreeBMW]

I just installed a 16cm2 non wastgated housing on my hx35. I had a 14cm2 banks housing with their Big Head wastegate.





I am just noticing some differances i was not expecting.



Peak boost down to 35. 4 PSI (peak with 14cm2 39. 8PSI)



EGTs have gone up... . i used to bearly hit 1300s on a long pull but now just crusing in 5th if i give it "go" pedal i can hit high 1300s.



I checked for boost leaks and retighted all the clamps (non were that loose)



can anyone put me at ease>?!?!



Thanks

 

[rjones]

I have the same probs too the EGT just dont climb as fast now but still gets to 1500*

 

[illflem]

sorry but,

I pretty much have the same mods as you and went though the same problems plus slow spoolup. Took the 16 off and went back to my old Banks housing. Problems solved. Same thing is happening to a friend, Piers recomended he go back to the stock housing, a 14 or one of the more pricey complete turbos...

 

[Tom C]

I also tried a 16cm housing. It ran much hotter and slow spool up. I went back to the stock housing and its runs great. I just control the egt's with my right foot.

 

[BushWakr - RIP]

As you go UP in housing size you will loose between 3-4 psi boost.

However you should not have an EGT increase unless the NonGated housing is pushed to it's max end of it's map. This will result in higher drive pressures and correspondingly higher EGT.

The wastegated 14cm likely helped keep you just inside the efficiency map of the turbo.



As an example, I installed a hybrid PDR HX35 and ran a nongated 14cm. I had very fast spoolup, and 42'ish psi boost.

I also hit 1700*F on a long dyno run, my results with that combo gave me 283. 6 RWHP @1700*F.

I changed out the 14cm to the nongated 16cm and now I hit about 38psi and can't break over 1400*F.

With this setup, I ran 38psi boost at a max EGT of 1350 - 1400*F and my numbers were 325. 9 RWHP today.



Regards, Bob.

 

[patrobertson]

My 16cm

When I installed my 16cm housing about week and a half to two weeks ago I did a 3000gsk at the same time and had a 11 plate full forward, I wasn't as happy as I thought I would be, took a bit to spool and I didn't get over 30-32 psi on a stock HX-35. Than I put in my 10 plate and it made a good difference, it does run warmer just cruising but when I get on it takes a lot longer to heat up and I can control it better where as my stock setup would bury the needle almost instantly if I held it at high rpms. Off the bottom its a little doggish but once I get to 2000rpm and it spools up it scoots, and now I can wind it out to 3000-3200 rpm.



Shane

 

[dpuckett]

I agree with BushWakr- the larger housings will flow more high RPM exhaust gasses, but at the expense of low RPM spool up. So you need to determine which RPM range you will be running at; are you going to be towing 15K# in the Rockies? Or will it be more of a daily driver, and occasionally towing a 5'er on weekend trips? For the former, I might go with a 16, since I'd be running in the 2300+ RPM range, and need the high end flow. FOr the latter, I'd go with a 14 gated or stock. I put a 12 on a 93, and it did excellent empty, and with an empty trailer, but EGTs got a little warm when I grossed 20K+ and went up a 6% grade. I have read the 12 gated should be good to about 250hp; anything above that, and you need the bigger housing. But... . If you run at lower RPMs, the smaller housing will give you more air at cruise, and if you stay under 2500, you shouldnt have any choking issues. Just my $. 02.

Daniel