GTM Performance Engineering: GTX V3 Twin Turbo Kit

1slow370

Also i just looked it up and other than the outer size the T25 plus is huge, if they fit the car you can get a full size GTX3582r better known as the GTX35/40r because it has a friggen 68mm GT40R turbine, the oversize t25 inlet is actually larger than a 2.125 v-band housing, and you can get it in either the .63 or .82 A/R. Lets hope that turbo fits.

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BlkNismo

I'm also interested in thoughts on the GTX2860 vs GT2860 for stock block applications.

Diabel

I'm on the MHI group buy but wonder is the GTX upgrade a good idea when I do not plan to build the engine? What is the added value (if any) when you want to stay on the stock motor? Especially when we have already promised the free upgrade from MHI to GT2860rs turbos.

What is the release date of GTX kit? Is it the same as MHI?

SPOHN

Well one day you will have to build and when that day comes you will have the goods to push that baby to way more than your car or skills can handle.

Added value for a stock block would be same power levels at lower boost which equals lower cylinder pressure. That's huge in my book.

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elperuano

Plus boost comes on little later which definitely helps with traction.

esfourteen

I plotted some boost levels against a rough calculation of a VHR for the gt2860 (stage1/2 turbos), gtx2863r and the gtx2867r.

if you plan on never making more than ~575whp (or dont mind running meth/e85), the gt2860 is a great turbo for 15psi or less on our engine. after 15psi you start entering the choke area of the compressor at high rpm (6k+) which will shorten the life of the turbo and blow hot air. (i don't have this graph handy but trust me, its choking)

If you're going for more than 600whp, the gtx2863R is a much better match, at 24psi its in the choke area up top so I wouldn't recommend running a lot of boost with this turbo on 93. still a great turbo for our engine and should produce 650+whp



in my opinion as far as efficiency is concerned, the 2867r looks like the best match for our engine if you want make power past 600 but still have a quick spooling turbo. these wont start running into the choke area on our engine until 25psi near redline, at that point you'd be producing somewhere near 700-750whp.

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Mkai0

Thanks for sharing this. Do you have any info about the gt2871r .86 AR turbos? Just called Mike last week and upgraded to these badboys. Hoping to get 600-650whp with a little methanol on a built block and built auto transmission.

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Neo187H

So is this kit available now? Or when will it actually be available for sale?

esfourteen

the gt2871r compressor map is very similar to the gtx version, most significant difference is that it tops out around 28psi, the gtx version is good to about 40psi.

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Mike@GTM

The issue with the GTX2860R is that you will not reach its peak efficiency island until 17psi of boost. It is really more geared towards an engine designed for boost from the outset with low compression. On the VQ37VHR with its 11:1 compression, the GTX2860R is not a good match. Granted, it will still "work", just not as well as the GTX2867. While the GTX2863 is an "OK" candidate for a stock motor, you don't really hit the peak efficiency island on the stock engine until higher boost levels than you can realistically run on pump gas.

The GTX2867R is the best candidate for the stock engine because you can run through a large portion of the high efficiency island for more of the powerband. That means less energy needs to be harvested from the exhaust gas to produce boost. Furthermore, the boost that is produced is at a lower temperature which means less heat needs to be dissipated by the intercooler and smaller cores can be used.

The bottom line is that I would recommend the GTX2867R since it is an excellent match for this engine.

The GTX2867R is definitely a good way to go, even on the stock engine as I pointed out above. If you are just looking to have boost on a budget, however, the GT2860RS is still an excellent choice.

We anticipate having this kit available to ship approximately 30 days after the MHI/Garrett kits start shipping.

Dzel

And thats?..

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chii370

too many different GTM kits. the first one, the MHI, and now this........ how am I supposed to know whats best for my car Im guessing the GTX is the new "flagship" setup? and MHI is like..... the budget version?

Jayhovah

I believe you hit the nail on the head.

Alstann

More or less.

Keep in mind, there is so much more to turbo kits than raw power. Generally speaking, all GTM turbo kits have the capability to produce more power than the stock motor can handle, which is estimated to be around 550-600whp. The differences in the kits allow for better efficiency and response, as well as extra headroom for different power paths.

For example - the GTX GTM kit comes with the GTX turbos, which many people would argue produce negligible increases in power since the efficiency maps are similar at low boost levels. However, at higher boost levels, the GTX flows very efficiently. Also, the GTX turbos have higher adiabatic efficiency overall, and would lead to better transient response and spool characteristics.

Also, the GTX kit comes with 1100cc injectors, and 340lph fuel pump. In other words, it's also full-E85 capable.

On the other hand, the MHI kit has smaller injectors/pump, and the turbos are journal bearing. But, that being said, you can totally make 550+whp with that kit. You can also look at the reliability and simplicity of the MHI turbos - turbos people have been using forever and they work great.


That's one thing about turbo cars - it totally changes the driving dynamic of the car. You'll be going from a car with a totally linear, all-motor powerband to a car that now has a delay due to lag and response with forced induction.

Big turbo cars have an inherent issue - they make great power and in a straight line with the right setup - they are fast as hell, but during dynamic driving events such as tracks, or even in the city and just cruising around - the car drives like a dog. You'll always be waiting for the boost to build - and by then, it's too slow. I believe in minimizing that boost delay and improving the response to behave as much as all-motor as possible - since I enjoy driving dynamically, and not just fast in a straight line. And yes, you could use external implements such as nitrous to help turbo spool and other ECU tricks, but we're just talking turbo basics.

It all comes down to what you are looking for in a kit. Me personally? I want the most efficient setup possible. A kit that will provide the best transient response, run the same power level on lower cylinder pressures and temperatures (possibly with E85), and has lots of headroom since I plan on a build down the line.

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COSMO

Iam kinda shocked that gtm is now trying upsell even more items when they cant seem to keep up with what they have now.. Very happy with my gtm kit so far keep in mind but come on gtm take care of your paying customers before overloading your business again upsetting ever more people..