starting to think gt28r wont cut 300rwkw

hey as you know had the dyno day yesterday and so i was interested in seeing what the girl could do with the new snails (gt28r) managed a 256rwkw pull at 20psi. now i am happy with the way the car drives it is incredibly streetable with heaps of power down low however i am starting to doubt the top end capabilities of these turbos. i have seen 3 or 4 gt28r dynos now 90ttz, don32 and myself and and we are all well off from 300rwkw. i have also seen tylers twinturbo net post but cannot really compare u.s dyno pulls to ours as they are quite different. so the highest gt28r dyno going around locally is mine i dont know how much tuning is left in it (running a hitec and it is pretty close to the limit) or if there are other factors associating to these figures (boost leaks i know i have a few) but these turbos just seem to run outta puff just after 6000rpm. please feel free to add your thoughts and ideas but i thought i would just bring this to the attention of the guys on the forum who are thinking 300 to 350rwkw is possible from these turbos. (i would love to be proven wrong but dont think they will cut 300rwkw)

below is a link to my dyno i know there isnt much information as it was only a power run but she is going back on the dyno next weekend so if you can suggest some other curves to be plotted i will request that they be included (if possible going to another dyno day for a differet car club)

http://www.icerslair.com/dyno/jezz84.JPG[/URL]

 

256rwkw @ 20psi ?

256rwkw @ 20psi seems very low.

Members have reached the 250rwkw mark with stock turbo's @ 14psi.

But turning the boost up isn't enough. Your engine needs the mods to accommodate the increased boost.

What other mods do you have on the car? Was it tuned when you installed the turbo's?

The other thing I'm concerned about are the Dyno places...seems there are a lot of variances inbetween different Dyno places around Aus. It's hard to tell which ones are right and which are wrong.

But yeah, I think your result @ 20psi should of been way higher...I was thinking around the 270 - 280rwkw range.

There could be a number of things wrong...

Cheers
Rob.

 

id be looking at charge air temperature

 

pffft, i think you could probably push 300rwkw on stock turbos if you have the supporting mods, etc (just)...

If you've just slapped a few gt28r turbos on without any other work, of course you aren't going to get 300rwkw on the dyno straight away.

Have you got honed exhaust manifolds? head work? anything?

Trust me dude, start of next year you'll see some big numbers from gt28r turbos over here in WA land

 

What supporting mods do you have??? I have high flowed std turbos getting 320rwkw@18psi

 

300-350rwkw is possible if you did head work, cams, manifolds etc. If you just changed the turbos only, then it would be unlikely that you will get those sort of gains. Seems like a lot of money to spend setting up when you're only making 30rwkw more than stock engines with less boost than 20psi.

I agree though, I doubt my GT28RS turbos will make a lot more than 350rwkw without going stupid on the boost because it is only on specific dynos that we have see those figures, usually the dyno of the shop who did all of the work to the car. A lot of people in the states are using turbos much larger than RS's to pull 400+rwkw. I think people still fail to realise how easily you can put a dyno reading out of wack even by the way you strap down the car.

 

to make near 300RWKW I think you would at least need 555 injectors and an ECU tune to suit. A Malpassi or Sard fuel pressure regulator will also enable to you to make more power by delivering more fuel and running more boost.

 

I think what he is saying is that he shouldn't have to be running > 20psi to be making near 300rwkw. I agree though, going over 300rwkw I would look at some bigger injectors.

 

I'm knocking on 300rwkw and have HKS turbo's, not sure what ones. I'm assuming GT28's of some description. Plus big exhaust, larger fuel pump, 555 injectors, pod filter, chipped ECU I think, EBC, and was running stock intercoolers at the time. That was 283rwkw at 18psi.
Hoping to crack 300 now with fmic and a few other tweaks.
Hope this gives you some idea what you should be able to expect.

Ben

 

Without hi lift cams and preferably bigger valves. You are pushing shit up hill getting 300RWKW.

You just physically can't get the air through the engine. Thats the bottom line.

 

i dont think thats true, i wouldnt be changing the cams untill all other possbility's were exhausted, at teh level of power he's talking about, a cam timing adjustment would most likely do

 

Is this directed at me?
Cos that's a bummer dude lol
Just shattered all my hopes and dreams, I was going to be happy to just crack 300 and then leave it for a while.... oh well, gotta get it back on a dyno and we'll see what improvment i've made if any.

Ben

 

I would spend the money on a valve grind instead of bigger valves, you will probably get more flow out of a grind as opposed to going larger valves in a Z32 head.

 

UAS Z isn't your average street Z. It has heaps more supporting mods.

 

Well mine has made about 40RWKW more than the stock turbo's at the same boost. I reckon there is easy another 30RWKW left in mine when I reach 20PSI and lean up the AFR so yeah, i'd be happy with 280RWKW. Don't care if some people have put down near that figure on stock turbo's. Put them on the same dyno and see what happens

 

Well.......................

.....my Zed (The Red Baron), made 280rwkw on stock turbos and injectors, stock internals, stock valves etc. etc. etc. What I did have done was instal and tune a Microtech ECU, free flow exhaust, pod filter, light U/drive pully, Bosch HP Fuel Pump, upgraded side mount intercoolers, oil cooler, radiator, and that's all. AND at only 14psi boost.

It is at AMEC now having new GT28R's installed, with 650cc injectors, lightened flywheel and an ACPT Carbon Fibre drive shaft among other suspension mods. I still do not really want to go over 15psi on stock internals.:zlove: It will be interesting to see what Dyno result comes of that

 

The CAMS are more important than bigger valves. But if you spend 2K on cams, a little extra for bigger valves aint a problem.

For your info, the difference between stock cams and JWT wild cams in terms of air flow is HUGE. Last time I looked for the same static pressure the wild cams let more than two times as as much air through the head as stock at maximum lift.

So basically beleive what you want, the normal cams are restrictive compared to good aftermarket cams. You want the power, pay the price!

Its not a matter of hitting a power level. Its a matter of the amount of boost you have to run to get it.

If you have a close look at the specs on Nixits car on TT net then have a look at the head and cams mods. That is why he can get the power he can at only 18 psi.

This is fundamental.

Fail to grasp the fundamentals about air flow through heads and you are bound to come up short on power.

 

Well how is it that Caz and Pex get around the 200-210RWKW with the same mods?

 

Beats me.............

.......are you sure that they are EXACTLY the same mods? Milanco Pro Dyno tunes my Zed, the same crowd that tunes Fleets