My R34 Gt-T Street/track Build/diary

[ssxRicho]

Brings a tear to the eye.

[blah_blah]

So thread update:

Car got tuned but there is a restriction, copy from my hypergear post

On 7/29/2013 at 11:06 PM, blah_blah said:

Can someone explain to me what causes too much exhaust back pressure?

Finally got the car tuned today on a build motor

Made 284 rwkw

Specs are a built forged, ported motor. SS2 turbo internal gate. 98 octane. Brae manifold, 3 inch JJR, not car, 3 inch hks cat back exhaust.

Trent said the turbo maybe a restriction. It had too much back pressure, causing the turbo to run hotter, and he couldnt run as much timing as he wanted too.

Stao said I have a 0.82 rear housing so it shouldn't be an issue

Car seamed to stop making power after 5-6k rpm

Does anyone have any ideas?

In saying that he said if I didnt have the restriction and it held boost I would be making ~ 330rwkw

Trent said the engine was running good and healthy which is a plus.

He said without the restriction I would be making a shitload of more power

Anyone have any ideas on what causes too much back pressure on the turbo exhaust housing? Thought 0.82 rear housing would be sufficient?

 

 

 

 

 

[scotty nm35]

Did you check the rear muffler for the 2.5 inch restrictive pipe so many have? Check the mid muffler too mate.

Perhaps it's time for better fuel?

[blah_blah]

Did you check the rear muffler for the 2.5 inch restrictive pipe so many have? Check the mid muffler too mate.

Perhaps it's time for better fuel?

Yeah I might have to try a dyno run with the cat dropped hey

Scotty and his e85, if there was ever an ambassador for e85 you would be it !

[34GeeTeeTee]

Scotty knows go the juice haha....

But yeah, drop the exhaust and see how it handles it?

[donmik]

Seeing the way the car hits boost and how quickly it hits max boost leads me to believe its not an exhaust restriction (it is running a 3" turbo back exhaust)

Being a 3" right through would make me "expect" a higher power figure before the exhaust system came into question...

I have seen the same turbos make higher power figures on stock motors, but this motor has a very highly modified cylinder head, which in my opinion is causing the turbo to over speed too quickly...

What works on a standard configuration will not necessarily work on this one...

As for the boost drop, COULD the standard bov be bleeding out once it spikes to max boost?

[Mohsen]

Ahhh I see

This is what you were talking about mick.

Interesting.

[blah_blah]

On 7/30/2013 at 0:36 PM, blah_blah said:

Also better pics of the dyno graph:

Green is my old setup: stock engine + china manifold

Blue: Is the forged ported engine + Brae manifold

Everything else is the same

 

[Shoota_77]

Whatever the issue is the good thing is it's something that you haven't changed from last time. Narrow it down to things that weren't changed. If it was just the engine build itself that changed then that theory doens't really help!

[Leroy Peterson]

How does it drive?

power may not be as high as you'd like (yet) but 500Nm is still a buttload of torque. revving it out high on the track might not be the fastest option looking at those graphs but it would still seriously move.

I reckon hit the track, keep it above 350Nm with shifting and have some fun. won't rev the shit out of it and can still break PB's. you've got solid foundations for 300kws now so it can done whenever really. (my 2c)

[blah_blah]

Whatever the issue is the good thing is it's something that you haven't changed from last time. Narrow it down to things that weren't changed. If it was just the engine build itself that changed then that theory doens't really help!

Engine is running strong and healthy, there is just a restriction somewhere else in the car. Likely to be turbo but will have a better idea in the coming weeks once we isolate other possible issues

How does it drive?

power may not be as high as you'd like (yet) but 500Nm is still a buttload of torque. revving it out high on the track might not be the fastest option looking at those graphs but it would still seriously move.

I reckon hit the track, keep it above 350Nm with shifting and have some fun. won't rev the shit out of it and can still break PB's. you've got solid foundations for 300kws now so it can done whenever really. (my 2c)

Yeah agreed 284rwkw is plenty for me at the track at the moment. Though Trent said as the turbo is working so hard the oil running through it is heating up the rest of the engine oil system. So I need to keep an eye on temps until I get a decent oil cooler. That and Trent said the choking of the engine at the high rpm range due to the restriction is not good for the engine.

So I have entered Sandown 11 August for a test day and will just shift at about 6,000 rpm

[gotRICE?]

Really nice build. Just read from the beginning.

Was reading about the original stock radiator blowing up. Looks to me like a single core NA radiator.

My R33 GTS25t had the same one. It was being quickly overpowered on the track after the GT30 install, so pulled it out and discovered how tiny it was. Luckily had Lithuims R33 right there in the drive to compare to, and his one was definitely an OEM twin core. Replaced with an item similar to your new one.

I wonder if the stock twin core's in ours failed and were replaced with cheaper single cores? Cheap bastards

Keep it up! Look forward to some videos!

[Deathvalley]

hey man how much did your first nistune cost you?

[blah_blah]

Really nice build. Just read from the beginning.

Was reading about the original stock radiator blowing up. Looks to me like a single core NA radiator.

My R33 GTS25t had the same one. It was being quickly overpowered on the track after the GT30 install, so pulled it out and discovered how tiny it was. Luckily had Lithuims R33 right there in the drive to compare to, and his one was definitely an OEM twin core. Replaced with an item similar to your new one.

I wonder if the stock twin core's in ours failed and were replaced with cheaper single cores? Cheap bastards

Keep it up! Look forward to some videos!

Not sure but apparently the stock GTT radiators were only 14mm thick about half the size of the R33 ones

New radiator definately working a crap load better keeping temps under control

hey man how much did your first nistune cost you?

Can't remember did it quite a few years ago

But would have been ~ $700 - $800 including the hardware and instalation and tuning costs

[blah_blah]

So first track day in about 10 months!

Did a track day at Sandown for its first shakedown of the car to see if anything would fall apart.

Coincidentally my best time was a 1:33.538 which was the same time as my best time when the car was stock

There was alot of traffic during the day so it was hard to string together any sort of hot laps

Looking at the race data, top speed is up about 10km/h but all my corner speeds were down by 5-15km/h pending on the corner

I think the car sitting on the tyres for 7 months in the one spot didnt really help the KU31/NItto Invo tyres at all. I think someone also mentioned that the track temps were very cold. It was about 16c and overcast that day i think!

In addition I was short shifting at 6,000rpm due to turbo issues so the car would sometimes bog down on upchanges.

Oil temps:

After 4 hot laps oil temps would reach 120c, then stabilise at about 125-130 after 2 further hot laps. Water temps were 80c measured at the bottem of the radiator. So about 90-100c up top

All in all though car didn't miss a beat and no issues with the engine which is good!

So items on the wishlist before the next track day:

4 x Yoko Advan AD08R's 265/35/18

Oil cooler

Adjustable front and rear lower control arms for -ve camber

Kaaz/Nismo 1.5 way diff (traction out of corners isn't the greatest)

Anyone got any idea's on brands for the control arms? Maybe I need sway bars too among other suspension bits? suspension is completely stock apart from Tein coilovers, which are apparently falling apart

I'll try upload a video of a session tonight. File is 1GB though and never uploaded to youtube before so ill see how I go!

[blah_blah]

Excuse the video quality. Only learning how to put videos together haha

So this is my best lap of the day. Traction out of the corners seems to be a bit of an issue. BMW pulls away on most corner exits

Excuse the beep in the video that is my oil temp warning going off at 120c haha

Ill upload a video of the whole session when I get time

[B-rice]

how did you get it to display the speedo and map. Thats quite useful for monitoring progress on some bends.

[34GeeTeeTee]

Excuse the beep in the video that is my oil temp warning going off at 120c haha

DANGER TO MANIFOLD

[blah_blah]

how did you get it to display the speedo and map. Thats quite useful for monitoring progress on some bends.

Go Pro for the Video. Racechrono for the data logging

Adobe Premier to overlay them

DANGER TO MANIFOLD

Floor pan of the car had extra wielding to ensure it would fall off

[blah_blah]

Managed to do some better quality vids last night

And also a full session from the last session of the day. At least I pass some cars in this video haha