Fast spooling T4 flanged turbos...

[eye-5]

Originally Posted by gawdzilla

so i didnt end up welding a new flange on. bought one but never got it welded. the old flange still had some good meat on it.. a little over 1/2" thick i'd say. i ended up taking the turbo and manifold to get decked. turns out the manifold needed some flattening but the ATP twinscroll turbine housing needed quite a bit of work. crappy casting i guess. so now everything is back together and sealing good. running no gasket. my spool time is back!... for now. probably until i do the next track day knowing my luck.

I had an issue with the vband downpipe leaking too, but that was resolved with a new clamp (old one kinda wore out and bent). i also got a new exhaust hanger added by the trans mount, so hopefully that relieves a lot of the stress the whole turbo/manifold sees from the downpipe and exhaust. previously i was just running the 3 hangers in the rear of the car.

I had this problem the turbo and exhaust kept coming loose at track days and adding the trans mount did the trick. It took a new down pipe and some ingenuity to get it to line up.

[gawdzilla]

here's a followup as the car stands now. got a full tune from MA-motorsports and they did a hell of a job. driveability, mid range, etc. drives like a well mannered car now. still running the T4 gt35r TS 1.06. this chart (orange lines) shows 20 psi after the tune, but it's tuned all the way down to about 10 psi. this is dyno dynamics as well - so insert whatever caveats there are for this type of dyno. my original was on a dynapack and the tune was sucky, and i'm definitely making more than 525 whp (dynapack) hp/tq at 5 psi less boost. ignore the old and busted blue lines, lol.

here's an internet comparison i found of a TS .78 gt35r also on a dyno dynamics if you want a boost reference:

i dont have the boost data on mine (tuner did not send to me) but i imagine the boost looks very similar to above, considering my hp #s are very similar per rpm

[juggernaut]

gawdzilla...is your setup on a sr20? I only ask because the comparison graph you posted with the TS .78 was on an RB26.

Amazingly, the TS T3 .78 GT35 does not seem to choke even on an RB26 when compared to your TS T4 1.06 setup.

Great results anyway - I always wanted to know how the T4 1.06 GT35 setup would go. Dyno's of these are as rare as hens teeth on the net. Thanks for posting.

[gawdzilla]

Oops I thought I specified. Mine is a 26 too so that's why I was saying it was comparable. Yea it's funny how the #s don't drop off on the .78, but it's also surprising his spool is not noticeably better. Maybe the boost needs to be raised before the smaller a/r chokes out or it may choke out with more revs. Mine was going to 8k rpm. Btw my manifold is not a real ts. Single wg only

[juggernaut]

Yes I suspect you would be right...that the .78 is more likely to choke in the higher rpm. Spool between the two is similar as you say....at some rpm points his hp is higher at others yours is higher.

His graph also shows intake temp (IT) lower than ambient temp (AT) so his dyno will be slightly down on power due to the correction factor compared a dyno where the IT is higher than the AT which is the usual case. These details nor your ramp rate are shown on your dyno....which I know is due to the new dyno dynamics software which doesn't show these details like it appeared on the old software.

[gawdzilla]

the shop tuned an rb26 z32 prior to mine with a T3 .82 35r, single scroll. i believe also a stock head with drop in cams, and also on pump gas 93 octane. the tuner said the t3 .82 was spooling faster and his psi overlay was shifted to the left of mine without any mid range overlap. it would have made sense for the TS and SS differences to show somewhere in the midrange, but they did not. the .82 SS looked to be a better choice. that was a bit of a surprise to me, but there are just too many factors to make a solid comparison.

just another factor for the above comparison... i'm not sure what gas the .72 35r above was using, but i believe better pump gas is available in australia? like i said, it's hard to compare across different dynos/setups even if the motor is the same.

i'm really excited about the driveability moreso than the numbers actually. the car is really well mannered and torquey now.

[juggernaut]

We have 98 octane in Australia which is equivalent to your 93.

As you've said, the main thing is your happy about the way drives.