ChrisW434

Thats reassuring to me that there is an issue. I believe my combo would be mid-to-high 600s rwhp when sorted. Refer pic (second one for context). I paid attention to bends and where it merged and all that. Maybe the engine wants to keep making power but just really dumps more exhaust volume in the exhaust than i expected and backpressure is building. I'll make a screamer for it and also try a dump pipe on the dyno

Thanks for chiming in Tao, i appreciate it. Looks like some exhaust mods will be happening shortly, in particular a screamer setup... I do have Kelford drop-in cams so hopefully it should make better power on less boost once its all sorted. Cheers for the detail in the response also, great service as always.

I agree with DBW benefits, i tried to "keep it simple" with cable when i bought the parts a few years ago, but it has made tuning for results more complex! Should have gone DBW lol...

Yeah mate, less than 1% throttle. I drove it again today, and i'm pretty convinced its the 'ghost cam' idle timing being present as i drive...

Yep i understand and agree. My exhaust is all v-band coupled and in sections, so i'll just make a screamer pipe and get a exhaust blank. I can back-to-back swap as required then 👍🏻 Sounds like even with decent (merged) exhaust/plumb-back size, it still may still be creating back-pressure at that boost level/exhaust volume level.... That explanation is basically what Tao was saying also

Yep sweet. The tuner mentioned that was an option

Yep, the wastegate is just bellow the turbo. I sort of eliminated the EWG setup was the issue as its 2.5" out of wastegate, merging about 700mm later into the 3.5" exhaust down near the trans. Tao did explain with E85 and the boost i want to run (30-35psi), changing to a screamer would make a big difference. I don't run a wastegate position sensor (like most streetcars) so i can't see in real time what the wastegate is doing, but i'm assuming it would be fully closed when running higher boost, thus taking the screamer setup out of the equation at full boost? Or would it actually crack open and bleed some exhaust out under big power?

Yes, the markings are correct. I considered that too.

Yeah , i actually based a few of my choices around Tao's setup. And wanted to see if i could push it that high. I messaged Tao directly and he suggested the screamer makes a big difference. I currently have an external 60mm Turbosmart gate (to allow low boost on p98 if required) And considering that is a lot easier to try than pulling and sending the head away for valvetrain inspection/setup, it would be worth a try. And, IATs were good, i cant remember numbers, but it started raising the temps a bit over that 25psi mark supposedly. Though running a good intercooler is key. Also, i made a mistake in my first post, the runs were on a wheel dyno, not a hub dyno as i originally stated (typo) so thats different also...

Hi again all, i got the GTT dyno'd and the car was down on power for what i believe it should be making (very common story i know)... The power curve is good, with great Lambda readings, and drives well apart from during very low speeds i.e: carparks (seperate thread for that issue). It has all the usual parts that i reckon are pretty well matched, and in some cases, overkill for my needs (i'm ok with that). 2.5L Neo with supporting mods, manual trans kelford drop-ins, Performance springs, Ferrea S/S exhaust valves Hypergear ATR45SS-2 (gtx3582 compare) 6boost, 3.5" exhaust, 60mm plumbback gate Plazma pro-series cooler, tophalf and 66mm TB. Haltech elite 2k on E85 , Ross triggers, R35 coils - Power peaked at 530rwhp on hub dyno at 8k (25psi boost). The tuner commented on how the engine wouldn't respond with more boost, as if there is a restriction somewhere. Tapped out at that power level.... Couple ideas for what would be choking up the engine would be ; - Plumbback causing backpressure, got some advice to convert to screamer - Valvespring tension incorrect, causing float at 25psi and up. I didn't test and shim the springs, i just installed them with a shim under each one. Perhaps the Ferrea locks are a different height? Torque curve is smooth all the way up, no erratic spikes on the curve, so not sure if its actually floating.. I reckon this setup should make over 600rwhp at peak with this setup.. Thoughts on either option, or another potential issue?

Yes, without looking at it, it appears the 0kph timing condition is something i should look at. The "lungeyness" was there before the last tune when the 'ghost-cam' got installed, but it's much worse now. I reckon that sounds like a big part of the issue, if not 100%. i'll bust out the laptop and spend some time looking through the settings, and make small changes via trial/error. thanks again for the detailed post 👍🏻

Hey there, TB is 66mm, so nothing too large. That initial very light tap (1%) on the throttle pedal sets off the crazy lungeing. It goes away if you let it settle or just throttle it more. Super annoying... its like the throttle is super touchy and the chassis starts reacting, possibly due to the tune in that map area..

Yep, i agree thats the direction i should go in. i forgot to mention something relevent; i asked the tuner to give it a chunky idle and to achieve that, the timing is different at zero-throttle. I reckon that may have something to do with it. As you say, datalogging would be the best way to check whats happening.. Cheers for the detailed response!

Hey all, The 34 GTT lunges violently if you touch the throttle at very low speeds (carpark), until you back off or throttle harder after the chassis has settled. I suspect the tune needs a little more work, but want to try some little haltech setting changes if possible to soften the hit when touching the throttle at walking pace. I suspect the remote mounted IAC (plaz top-half w/cable TB) may be partly ,or fully, to blame as the airspeed at that low rom and load could possibly be disturbed with a laggy remote IAC. The driveline has 1pce driveshaft and twin-plate clutch that "may" exaggerate the issue.... Does anyone have any thoughts, or have experienced this? What settings in the Haltech could soften the jerkiness? Say initial 0-2% throttle opening at less than 1200rpm..? Thanks in advance!

Sounds like you did it correctly then...

Nothing seems to change when hot with mine. When you did the measurements for the build, is there enough gap (end-play)in the trans tailhousing to allow for any changes with heat/flex etc?

I have an AlphaOmega 1piece tailshaft in my 34 GTT, no issues here. Granted, i havent spent much time going 140+ though yet. Still, love it

I'm not sure about what the work would cost locally yet, hence the question and request for info. I don't know if $600 is realistic here in Aust, just not keen to get the wheel sent to Singapore (or anywhere overseas for that matter). Trying to see what others have done successfully. Seems like there's few different ways to go about it, but quality work isn't cheap, i do agree. Maybe a company like the one below...?

Well that actually sounds better. I'll chase that option up, happy to pay for a quality job. Thanks for the advice!

Yeah thats i what i was thinking, prob still the best option, BYO cover and pay for install

Whoa, not so sure about that option 😄

Sounds good, thanks for the reply!

So i guess its a real delicate job to reupholster it then? Carefully remove worn-out skin then go again?

Just worth doing the cover straight up then by the looks. Cheers!

Hey! i'm considering stripping back the worn off pleather from my 34's steering wheel, until i get it reupholstered in the future. Does anyone know if its a smooth, usable finish underneath, or is it a bad idea? cheers!