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Would you be willing to say that this Z1 comparaison is safe ? http://www.z1motorsports.com/product_info.php?products_id=6556

I'm mainly interesting in the 2860 vs 2863. My ultimate goal would be to have gt-ss response I so loved with -5 power. ( I owned both setup on same engine and type-b cam so comparaison is easier). Top-end appears similar and don't really care about that anyways. More interesting in the mid/down low power.

Here we go, I found one of the graphs on my phone, this is not the max power figure and final tune, but very close to what it was when finished. It was only a bit more in the top end that really changed. It is a before and after graph. It ended up exactly 100hp more at 648hpatw when it was cranked up to 33psi, but that was the limit of the turbos well and truly.

The actual figure we ended up getting out of the -5's was actually was 580hpatw but was really straining them real bad and the mid range was still 90hp less regardless, so the 90hp mid range increase was a real world change that was the biggest difference out of the GTX 63 upgrade and on track coming out of corners in 3rd, holy moly oversteer even with full torque split turned up 295's all round in a Semi 03G Dunlop :)

This is the real world differences that were seen being nice and conservative.

90hp increase mid range,

68hp top end increase.

100rpm better response.

It may not seem like much, but on track it was a totally different car to drive, especially on the limit, It started to feel like a real hardcore time attack weapon.

I won the fastest GTR lap record times in QLD by almost a second and I'm sure if it went back to Victoria a lot of people should be very worried including modified R35 owners, they are nowhere near safe from this 34.

Anyway it is now sold to a nice young fellow in Sydney and he will be doing the same with the car as I was and Aaron P. I think he will need a bit of time to get used to it though for competitive lap times, but he will be up there soon I'm sure, a very sensible person who will edge it up bit by bit.
I hope this helps some of you out.

NextUp Performance in QLD were the ones looking after my car since RacePace.

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Interesting. so I suspect the 2860 are the -9 equivalent and the 63 must be -5s. ( by going with nissanforlife's resume saying the spool was barely better than -5s)

Yes but the mid range is a huge improvement over -5's, the GTX 63's in the -5 housing is a huge improvement over stock -5's.

I took my GTX2860's out of my setup and put the -5's in, that I fitted brass bearing cages to.

I'll hang onto the GTX's and get my 2530 front housings machined to suit the GTX's, then it'll will be on again! ;)

Biggest difference I noticed between the GT series and GTX series is the intake noise/spool. The -5's are a lot noisier with whooshing, lots of air movement, and the GTX's being pretty quiet even at 24-25PSI boost (keeping in mind that this is on BP98 only).

That is one angry looking car! Yum yum

By looking at the engine bay and having stock pipe work I'm assuming you have the stock style comp housings?

There is no denying that graph comparison, it's quite a significant improvement. What size cams and comp ratio is it? Being an ex Racepace car, they would be on the smaller side if not standard items unless you have changed them.

Got me thinking about putting 60 mm versions in my own car. I don't want anymore power, just bring it in even earlier than it does.

I'd love to know the weight differences of the cast -5 wheel and the 60/63/67 mm GTX wheels.

Simon had his -5 comp housings machined to bolt onto the GTX turbo's :)

I'm about to do the same with the 2530 comp housings I have.

My GTX2860's are going cheap ;) will probably hang onto them though.

Yes but the mid range is a huge improvement over -5's, the GTX 63's in the -5 housing is a huge improvement over stock -5's.

I get your point, it might feel like it spool earlier because of the huge improvement. I just wish of a turbo that could have the response of the -9 with the power of the -5 lol I feel like 600whp is enought for a street car driving in a city with not so much open space.

But you got me really confused now.. I read elsewhere that spool is pretty much the same between all 3 turbos because the wheel was the same ( don't quote me !! cant remember exactly why..)

P.S: How much torque improvement did you get ?

Edited by cobrAA

But you got me really confused now.. I read elsewhere that spool is pretty much the same between all 3 turbos because the wheel was the same ( don't quote me !! cant remember exactly why..)

I wouldn't believe that for a second otherwise the smaller versions wouldn't exist.

Simon, were those runs done in 4th gear? It looks like it but it looks like it's only running to 7300-7400 rpm. In assuming 265/35 x 18 tyre with stock diff ratios.

Yeah 4th gear Piggaz.

The tyres were 295/30/18's. Being a RP 2.8L it didn't need to rev all that much and I never drove it out of the adequate power band, shifting at 7500-8000 was always heaps, even shifting at 7000 was enough.

It had stock Diff ratios as always was one for some big 5th to 6th gear action at certain cough cough, race tracks.

The torque improvement I don't remember as I don't know what I started with, but the final figure was 802 ft ibs of Torque, and man did it feel like it. Gee I still get goosebumps from thinking about it, really wish I didn't have to sell her.

Yeah 4th gear Piggaz.

The tyres were 295/30/18's. Being a RP 2.8L it didn't need to rev all that much and I never drove it out of the adequate power band, shifting at 7500-8000 was always heaps, even shifting at 7000 was enough.

It had stock Diff ratios as always was one for some big 5th to 6th gear action at certain cough cough, race tracks.

The torque improvement I don't remember as I don't know what I started with, but the final figure was 802 ft ibs of Torque, and man did it feel like it. Gee I still get goosebumps from thinking about it, really wish I didn't have to sell her.

I'll play around with the graph tonight. Obviously different dynos and stuff but it will give a good indication.

If they're 63's one could only wonder what the 60 mm curve would look like.

Who did the machine work on the comp housings? You are an evil man posting stuff up like this!

Compared to the -5's, what was the on/off/on throttle response like? Noticeable difference to the normal cast -5's?

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.

It def

I'll play around with the graph tonight. Obviously different dynos and stuff but it will give a good indication.

If they're 63's one could only wonder what the 60 mm curve would look like.

Who did the machine work on the comp housings? You are an evil man posting stuff up like this!

Compared to the -5's, what was the on/off/on throttle response like? Noticeable difference to the normal cast -5's?

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.

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