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98 R34 Gt-four


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Turned up the boost a little today. I had to remove the rear turbo inlet tube to get to both of the wastegate arms. I turned them two full turns from where they were. When I first installed the HKS actuators, they were about .5 bar, now they go to about .65-.70. I didnt log it and I was just out driving and not paying too much attention. In a couple days I will turn the arms another two turns to see if it goes another .2 bar. It is going to take some motivation to turn up the boost more considering all I have to remove to adjust the arms. it Takes about an hour to do it too. Maybe it will take less because today I had to run upstares because I kept forgetting tools. I can feel it gets too rich up top or not enough timing. I got a map ready to use that has a more linear fuel curve and some expanded timing maps for the more boost I may drop in later. I really need someway to log knock, may look into the Radio Shack method.

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Yesterday I drop a timing map that I thought might take care of some of the Low Gear High Load pinging that I have been experiencing. I knew that it has been caused by the higher compression so I know that base timing would be less as higher comp. motors usually have less base timing. After looking at other timing maps, like the RB25, I decided to trim 5 degrees of the entire lower section of the ignition maps. So far it has made a vast improvement to intitial take off and low load to medium load transitions. I think I may some less timing in the 2000rpm areas though, they were only trimmed about 3 degrees. So now when the car is timed, it will be to 15 degrees with a timing light, not the stock 20. All this and I didnt have to touch the cam angle sensor.

This picture shows both timing Maps, Green is stock RB26 and red is my concoction. After I am done, there should be a little more red in the High Load High RPM area. The red there now is the HKS bootleg tune I got from an HKS tuned ECU that I got a while ago.

pingchanges.jpg

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  • 2 weeks later...

I aquired a front swaybar yesterday from an R32 GTR and ordered a rear GTR bar from Upgarage. I did some research and figured I am losing some handling ability because I am running the GTS25T bar in the back. I figure that the swaybar setup of the 2wd would need to be way different than the AWD setup. The current bars are 22mm up front and 18mm in the rear. The GTR setup is a 24mm bar upfront and 25mm in the rear. I guess the AWD needs a stiffer rear to combat the understeer. The thing is I think I need to drop the subframe a little to change the front one.

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Awesome car! This might sound silly are you running 450hp at wheels or at the engine?

Not really running the power yet. It is only at .65bar now. I did feel the clutch slip with this boost level, so no turning up the boost will have to wait till I upgrade the clutch. My goals are really not at the wheels though. I am really shooting for 50% more power, not necesarily a power number. I am going for feel and tuning to see what I can get. Later when the clutch is good, I am going to play around with the timing map up top to see what numbers are there. I just need access to some knock monitoring equipment. End state will be 1 bar with tune. Then I will see how much the MAFs are flowing and see how close to maxed out.

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Not really running the power yet. It is only at .65bar now. I did feel the clutch slip with this boost level, so no turning up the boost will have to wait till I upgrade the clutch. My goals are really not at the wheels though. I am really shooting for 50% more power, not necesarily a power number. I am going for feel and tuning to see what I can get. Later when the clutch is good, I am going to play around with the timing map up top to see what numbers are there. I just need access to some knock monitoring equipment. End state will be 1 bar with tune. Then I will see how much the MAFs are flowing and see how close to maxed out.

Thats fair enough. I understand what you trying to do. My 32 GTR runs 1bar of boost it make 343.8rwhp with a remap ECU, and for clutch I'm using ORC twin plate rated for 700ps. I know a Apexi power FC was knock monitoring thing on there.

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My 32 GTR runs 1bar of boost it make 343.8rwhp with a remap ECU,

I hope to make more as I am not running the stock turbos.

The clutch I am looking it is the Nismo GMaxII. I know someone that installed one on their R34 GTR and they said it feels and drives like a stock clutch. I am sold on that idea.

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I hope to make more as I am not running the stock turbos.

The clutch I am looking it is the Nismo GMaxII. I know someone that installed one on their R34 GTR and they said it feels and drives like a stock clutch. I am sold on that idea.

That fair enough. What turbos are you running?

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very neat build. i like the attention to detail that your going to :D. you should have left the rb25 rocker cover, valley cover and cam gear cover on. then noone would suspect there was a 26 in there at all :P

looking good

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very neat build. i like the attention to detail that your going to :D . you should have left the rb25 rocker cover, valley cover and cam gear cover on. then noone would suspect there was a 26 in there at all :P

looking good

Funny thing is when I had the other cam covers on, guys would ask me how hard it was to twin turbo and ITB the RB25. I told them that it was easier than putting 25 cam covers on a 26.

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  • 1 month later...
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  • 11 months later...

Winston, im also modding my gt-four, but im just starting. Any ideas on which coilovers to get? i was looking at BC racing v1's which are pretty cheap, $1.2k for front and back. Also, do you know if the shocks are fork type or eyelet type?

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Trying to decide what to do about suspension setups.

Right now I am running Billsteins and Nismo springs designed for the R33 GTR, but that was just to get me by. Next thing will be R34 GTR coilovers of some sort, but I dont know what. Obviously will be used from Upgarage but I dont know what. And then I am think about poly bushings, but I dont know where to get AWD stuff for the fron. I am also wanting to get wider wheels for the front as my wheels are staggered (yuck for AWD). After all this I need a way to adjust camber. I just need a setup for what little touge we have on our tiny island.

I am thinking Tein flex with 275 rubber all around. What camber settings?

Winston, im also modding my gt-four, but im just starting. Any ideas on which coilovers to get? i was looking at BC racing v1's which are pretty cheap, $1.2k for front and back. Also, do you know if the shocks are fork type or eyelet type?

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