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It def

It def felt heaps better with the throttle with the GTX's but with some smaller overlap cams would have been even better again I reckon.

I'm not sure who did the machine work to my front housings, it could have been JHH Racing in QLD ?

What's evil posting things like what up?..........lol.

Haha!!!!

Do you know what cams were in it?

There is still a little lag after a gear change with the -5's. It's funny because the 63 mm GTX is a larger wheel than the -5 comp wheel.

Haha!!!!

Do you know what cams were in it?

There is still a little lag after a gear change with the -5's. It's funny because the 63 mm GTX is a larger wheel than the -5 comp wheel.

Yeah they were 272 / 9.7's. Putting some 260's in it with 11.0 lift would have been better for sure and probably would have done that if I kept it :)

Very strange choice for a RP car, that's for sure.

If it had a curve like that with massive 272's it would have been stupid with a cam in the 250-260 range, for sure!

RacePace didn't put the cams in, that was done later in QLD, but I would have def gone down to something smaller. I was talked into it some time ago in an attempt to try and see if we could get it revving a bit more up top. It was more of an exploration thing not something that was supposed to be permanent. You could only imagine with the smaller cams how much better it could have been !!

some good driving there - they do sound different to my -5s, definitely quieter & not as 'whooshie' as sean quoted earlier.

how much power was it running on this clip? its a handful :)

This is a video demonstrating the noise of the GTX wheels, never mind the the short shifting I was actually nursing some coil packs that were starting to break down and had turned the boost down a bit too as a result, but you can really hear that shrieking at mid throttle noise and it was addicting as , I loved it.

The sad thing was I finally got the car running at 648hp with stability in the end but never got a competitive lap at this level as things like coil packs and a blown clutch destroyed two of my days before I could really dial myself in at the power level for some Lap times. I still managed to kill the lap time record with 550hp, so with a 100hp more would have been nice, but I couldn't keep going back trying in the end as I was already living in Perth and flying back to my car in Brisbane all the time to do it all.
I think the new owner will enjoy exploring it's huge potential still yet to be proven in lap times.
Guys if you have a stroker RB26 the GTX 2863 conversion was worth it every day of the week.
I also must add that I always ran E85 full time even on the street.

some good driving there - they do sound different to my -5s, definitely quieter & not as 'whooshie' as sean quoted earlier.

how much power was it running on this clip? its a handful :)

It was around the 580hp mark there, but can't be too sure as I was only tuning via the laptop at the track trying to manage the coil pack issue. Sadly the next round saw the boost wound down even further as the coils really started to break down. Once that insulation starts to give way it just get worse at a fast rate aye........lol. It was all my fault too, I left the coil pack cover on before the day started, and once the first two laps were down (One being an out lap) the started their decline :( This sadly was the second session when I had already turned the boost down, and the first two laps at full power wasn't recorded as I got my camera settings wrong. Anyway the memory of this car will never leave me and I feel very fortunate to have owned such a car at all, so I am grateful for that.

I you look on my youtube account with this video I have some other footage at 550hp, and it actually looks cleaner and faster, but no GTX noise.

This was at 550hpatw and was my fastest times at this track on this day with a 55.9 and was only on the -5's, not much in-car footage due to more camera issues.........lol, but my awesome GF Andrea and my mum had me covered for footage from the pit wall :)
You can clearly hear the lack of turbo noise in this video compared to the GTX's in the other video. This track isn't the best layout either and doesn't really take much skill to drive on it, but it gives you an indication to where the car is at in terms of performance and it really makes you sort out cooling issues here because there are a lot of straights and you always seem to be pushing the power.

I know I'm getting a bit of topic in some of my posts, but I thought it was a good thing to put a variety of stuff up in relation to how my car evolved with before and after footage and performance differences, and I hope I can help people decide which route to take in their quest for better performance.
At the end of the day there were some things I would have done a little differently, but all in all I was very, very happy with my car and the way it performed and the GTX 2863 into -5 Mod would have been quite a big highlight through it all.

An RB with 3.0L capacity and above with a set of 2867's would have been my dream build really and if anyone does have a bigger capacity RB26 I would be thinking very seriously about going this way and I would have not hesitated at all. Maybe a Nitto 3.2L kit into an OS Giken Blocked 3.0L would be my ideal way forward if money were no object. I did get quoted around the 60k mark for this as long as I gave them my 28, eeeeeeek.

I hope someone builds a mental street/track car with the 67's on it, because I reckon they would be somewhere in the 700-730 atw area quite easily, and as for the torque figure, I dread to think, let alone drive it :)

  • Like 1

Simon, in that first video it sounds like they're surging (not shuffle but surge). It could be just the video though.

I have just done an overlay between your graph and mine. Obviously its a little rough but I was going up in 250 RPM points.At 4500 RPM we are the same, you overtake by a rough average of 20-30 kw then fall away at around 6300 RPM. Different dyno's and whatnot so it isn't the most accurate thing.

Now, if you went from 550 WHP to 632 WHP (on this sheet you posted) and nothing else changed, then that is farken silly. Can you remember what boost level the -5's were running to achieve that?

I spoke to the guy that tunes my car and he said to go the 63's. Now considering the -5's are a 360 HP turbo, 60's are a 400 HP turbo and the 63's are a 430 HP turbo, I'm not sure if I need the 63's. The 60's should (on my engine seeing that the -5's have already done 472 rwkw) do 500 with a much better curve to match (as you have not given away anything at any point), couple that with a 250 degree at 11 ish mm lift and it would be silly. What I am really curious about is that throttle response/lag between gears. It doesn't exist!

Also, Gav from WA went from -5's to 63 mm GTX's and the last time I spoke to him, he was going to go the 67's. I wonder where our little rear housing is going put the white flag up and call enough?

  • Like 1

Guys if you have a stroker RB26 the GTX 2863 conversion was worth it every day of the week.

ahh I thought you were 2.6 not 2.8. I'm only 2.6 so I'm leaning toward the gtx2860 instead, I'm scared to regret my choice tho :(

1) I asked sky-enginer, a shop in NZ ( i believe..) and they seems to have a bit of experience with the gtx and they said the difference in spool is ''about 200-300rpm''

2) Then, I asked z1motorsport who make a kit for 300zx with gtx, they're answer was : I would go with the 63 for more power and the lag isn’t that bad.

3) and finally , you, who is posting excellent result from gtx63.

This doesnt make the decision really easy lol!!

2.6 = 60's.

They're still a 400 hp turbo each.

The threshold might not be much on the V6 3.0 but it might be a different story on a shorter stroke engine minus 430 cc. The bigger engine will soak it up, the 2.6 needs all the help it can get.

Simon, in that first video it sounds like they're surging (not shuffle but surge). It could be just the video though.

I have just done an overlay between your graph and mine. Obviously its a little rough but I was going up in 250 RPM points.At 4500 RPM we are the same, you overtake by a rough average of 20-30 kw then fall away at around 6300 RPM. Different dyno's and whatnot so it isn't the most accurate thing.

Now, if you went from 550 WHP to 632 WHP (on this sheet you posted) and nothing else changed, then that is farken silly. Can you remember what boost level the -5's were running to achieve that?

I spoke to the guy that tunes my car and he said to go the 63's. Now considering the -5's are a 360 HP turbo, 60's are a 400 HP turbo and the 63's are a 430 HP turbo, I'm not sure if I need the 63's. The 60's should (on my engine seeing that the -5's have already done 472 rwkw) do 500 with a much better curve to match (as you have not given away anything at any point), couple that with a 250 degree at 11 ish mm lift and it would be silly. What I am really curious about is that throttle response/lag between gears. It doesn't exist!

Also, Gav from WA went from -5's to 63 mm GTX's and the last time I spoke to him, he was going to go the 67's. I wonder where our little rear housing is going put the white flag up and call enough?

Piggaz, didn't you already had 63s on a RB28 ? :P

2.6 = 60's.

They're still a 400 hp turbo each.

that's what I'm thinking, but you know just like I do, we can't simply add up ( i have 360hp turbos, I'm getting 400hp turbos so obviously, I will be making 80hp more) the number. I hope the gtx2860 can offer me the response of my previous GT-SS while still offering the same power/torque as my current -5s, if its more, then thats just bonus :)

OK sweet thanks for the heads up has defiantly helped me make my mind up. Going to go with the 63's on a 2.8 and squeeze em for all there got lol..

Any benefit to using the GTX housing rather than the -5? Obviously bit more work to put together with piping but you think the anti surge machining would be a benefit or worse? Do most people just use the -5 housing coz it easier?

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