Gt3071r (90t) On A Neo

[drgnball34]

what you guys reckon ??? Will it be " street friendly " ? or light switch?

[discopotato03]

L S , won't bolt up .

[discopotato03]

You will find turbo engines that need high boost pressure to achieve the desired horsepower are going to need high fuel rail pressure just to keep the head of pressure over manifold pressure . I think you can do better than that turbo for the power , something with better exhaust flow through the turbine side would help . That 90T turbine in the "overbored" GT28 turbine housing is known to perform poorly and the .64AR ratio is going to choke the living shite out of it .

The propper Garrett GT3071R with the full sized (and unmolested) 60 x 55mm 84 trim turbine in a REAL GT30 turbine housing works much better . The above thing may have an integral wastegate but the other compromises (T28 flange and butchered GT28 housing) just don't work well enough .

Sorry to be negative but I think the GT3071R "Wastegated" creates too many other issues and fixing them is not cost effective .

Cheers A .

[drgnball34]

cheers for the input...Any feedback is good

[drgnball34]

what turbo and specs do u recommened for power goal of 280rwkw?

[discopotato03]

As always it depends on what else is upgraded to suit and if you intent to spend much time at that 280Kw level .

To make 280Kw divide by 3 and multiply by 4 to get approx Hp or ~ 375 . Divide 375 by 11 to get required lbs of air = 34.1 plus 10% = 37.5lbs . 0.6 times air in lbs gives a fair air flow to exhaust flow ratio so 22.5lbs exhaust .

The closest match I can find is the GT3071R which has ~ 45lbs air and ~ 23lbs exhaust flow with a GT30 .82AR ratio turbine housing . It does not have an integral wastegate . That particular GT3071R is cartridge no 700177-0023 or -5023 , it does not have a turbo unit number because its only sold by Garrett as a cartridge to which you add your choise of Garrett exhaust and compressor housing kits . ATP turbo in the US can supply it complete with a choise of .63 .82 or 1.06AR ratio exhaust housings .

The closest thing in a HKS would be the GT2835 Pro S which also has a T3 mount flange but also an integral wastegate . This one may be a tad shorter on exhaust flow but some want the convienence of the integral wastegate .

Garrett is supposed to be releasing a new .82AR ratio GT30 integral gate T3 flanged housing which has gone back to late July - production lead times I'm told . This on the above mentioned GT3071R would be my choise ATM . The HKS Cast low mount exhaust manifold would help but can't promise the turbo would clear the engine mount and bodywork .

You need to be real sure 280Kw is what you really want and that the engine can stand up to that figure reliably . I reckon 240 Kw and the state of tune that could have would be nicer to drive and easier to live with in a road driven R34 but thats my ideals only . The R34 Neo's turbo in GCG's high flow form may just about reach that 240Kw figure with the right supporting mods and goes - bolt .

Your call .

[Busky2k]

Why not the GT30R? Seems like an ideal turbo... Although the HKS 2835 Pro S is a nice choice, just a little expensive though.

[carl h]

a proper 30r will clear just fine on a rb20 (and presumably a 25) using a hks manifold, this is how ive got my car setup.

[discopotato03]

Because the GT30R uses a 76mm 56 trim compressor capable of more like 400Kw . The extra unused compressor capacity has to be paid for in turbine energy regardless of if it used or not . So basically you'd get extra lag for no worthwhile reason .

Cheers .

[Busky2k]

But hes after 280rwkw, not 280 flywheel kw so thats a good 330 flywheel kw, which is more suited to the GT30R comp? Seems the GT3071R comp will be near its limits. But your right about the lag.

[discopotato03]

The problem with the GT30R is that its a bit short on turbine area itself . Its maps show it as having ~ 53lbs air capacity but the turbine map "flat lines" at ~ 26 and a bit lbs (and thats in its largest 1.06AR turbine housing form) so not really enough . If you divide the turbine flow number into the compressor flow number you get .50 or 50% which is not enough ideally .

The original Garrett bush bearing GT37 turbo (GT30R turbo uses a GT37 compressor as does HKS and why they call theirs GT30-37) is powered by a 72.5mm GT37 turbine which is not short on exhaust flow . A better match for petrol would have been something in between the GT30 turbine (60mm) and GT35 turbine (68mm) PROVIDED you really needed all that the 56T GT37 compressor can pump .

If you compare the 56T GT37 compressor map to the 56T GT35 map (GT3071R's comp) the 35 map is not too far behind the 37 in the flow stakes . Some of this is because the GT37 compressor is in a TO4E housing which was designed for 76mm compressors . The GT35 compressor is also in a TO4E housing in GT3071R form though the AR ratio is .5 rather than .6 and its snout is not port shrouded .

HKS had a fair idea that the GT30 turbine GT37 compressor combination could be a bit laggy in large or 56 compressor trim so they offered it in 48 and 52 compressor trim as well . This is part of the reason why some of their GT3037's respond better and get some boost and torque happening earlier than the Garrett GT30R can . A while back Garrett was developing a competition turbocharger for CART and WRC (probably Indi as well) known as the TR30R . The GT3071R ended up being the productionised cousin of the TR30R and is a better way of achieving what the smaller trim GT3037's can do . Compressor maps of the 48 and 52 trim GT37 maps are hard to find but the results are very similar to the 52 and 56 trim GT35 wheels . Just in case you don't know GT37 compressors are generally 76mm and GT35 71mm .

Garrett could have used smaller turbine trims earlier than they have which would have allowed them to go up a family on turbines for much of their compressor range . The GT3071R is one example of the turbine upsize though the trim at 84 did not change .

It has happened with the recently developed GT4088R where the turbine trim is 78 . It is also significant that the HKS marketed T51R is using a 76 trim turbine while the garden variety Garrett marketed GT4294R makes do with an 84 trim turbine of the same family . There is nothing to stop Garrett using 76-80 trim versions of their GT30 and GT35 turbines , the GT40 and 42's are already in use .

I think the way you should look at it is that rather than the GT3071R's wheel being near the limit its closer to being in sync with its turbine sides flow potential .

Cheers A .

[rb26s13]

280rwkw? in bolt on form.. cant go past GTRS with supporting mods.. people have pushed 300rwkw with them.. so why not? minimal lag.. good power curve.. thats wat i'd be choosing to get that sort of power figure

[Roy]

I have heard ppl quoting 300 odd from GT-RS but noone ever seems to make it. Well at least not on the forums that i visit

[paulr33]

with gt-rs

300rwkw on rb25det non neo with cams is do-able

300rwkw on rb25det neo is unseen (that i know of)

pete has gcg hiflow and cams and makes 250rwkw

i think matt has 2835 pro and made somewhere around 250rwkw

[rb26s13]

neo with cams than.. the response of a gtrs on a rb25 is amazing.. he's after 280rwkw right.. well non neo gets 300 with cams.. a neo should get similar with cams than i'd imagine.. 280rwkw with gtrs lag would be wat i'd want.. rather than 280rwkw with gt30 lag..