Gt3071R V Gt3076R

[Mick_o]

what gear was 18psi at 3000 on ya gt? My GTX is prob 3800 @ 21psi second gear internal gated on 98

yeah im thinkg bout the .82 external wastegate 56t on bp98 i used to have a 3071 that made 280rwkw on 18psi but wasnt a very big pull but now i have a different rb25 which is alot healthier

[jet2nv]

2nd gear the engine was shit i couldnt even do a burnout it was that bad lol

[GTScotT]

yeah im thinkg bout the .82 external wastegate 56t on bp98 i used to have a 3071 that made 280rwkw on 18psi but wasnt a very big pull but now i have a different rb25 which is alot healthier

mate if you want an easy 300 go the kando t67

it is arguably similar in response to a 56T 3076 but is $800 delivered and actually gets about 330kw on 20psi

800 will buy you a 3076 housing... its good value and theres a massive thread on them now. please read it.

[jet2nv]

yeah i might have a read

i do prefer garretts and the gt3076 i can for 1300 so i would prob rather get a brand new garrett over a kando but ill look into it

[Harey]

I think the T67 is a fantastic turbo but needs an external wastegate and really should have an aftermarket exhaust manifold compared to the 3076 which does not need either so puts it really in the next category up.

[jet2nv]

yeah id prefer a ball bearing and already have all the lines for water and oil if i was goin down the kando road id go see my best mate STAO and get a atr43g3ss for the same price as the kando t67

[R31Nismoid]

never really updated this. well here it was as of a few weeks ago. currently sourcing bigger gate springs and going e85 in the next week or so

Interesting on your graph - it almost looks like the 56T is actually surging around the 3000rpm mark.

My GT3040 (the 600hp one) did a similar thing, wasn't quite as severe but it also started to ramp, drop away a little, and then re-ramp again.

It was *barely* audible unless in specific conditions, but it was hurting the performance none the less.

Did you notice any surge around that point with the 56T? It's certainly not known for it!

[Jap_star]

Be interesting to compare our setups once mine is on E85 next week as our setups are similar when are you seeing full boost and what size are your injectors mate?

Ive got 850cc injectors a tomei pump and a GTX3071R internal gated

Full boost in 4th is about 3200. Didnt change at all when I went e85. And I'm using nismo 740cc and Bosch 044 pump.

Nismoid; Mines the 52t. I don't notice any surging

[R31Nismoid]

The comparo graph though (from page 3) the blue line vs the red line.

Ah mis-read, so it was a 52T just a housing change.

The blue graph has very "suspect" dips that usually come with surge as mine was exactly the same, interesting either way

If ya didnt notice then might have just been tune or something.

[Jap_star]

Heres the E85 graph from the tune on Tuesday. This is is 13.3psi, more coming soon

[Jap_star]

the more i read about surge, the more i think your on to something

[GTScotT]

you have the antisurge .60 front though right?

[Jap_star]

yep.

also it seems its down about 20rwkw at the 3080rpm marker over both other set ups.

Martin did say it kept wheel spinning around the 3000rpm mark, would that do it also.?

[Simon-S14]

56T anti surge housing here and zero surge related issues.

[Jap_star]

There seems to be no one with the 56t having surge issues. Could just be 52t related

[R31Nismoid]

yep.

also it seems its down about 20rwkw at the 3080rpm marker over both other set ups.

Martin did say it kept wheel spinning around the 3000rpm mark, would that do it also.?

Well wheelspin would cause those dips

But it shouldn't be turning tyres if strapped right or the ramp rate gets changed to suit

[Jap_star]

This tune was done on federal RSRs. The last one on potenza re001s that were a lot wider.

The only thing that's changed between then is the fuel and the rear tyres. And last time it had no dips. Might just go back with the potenzas and see how it goes

[JonnoHR31]

semi slicks are no good on dynos, get some normal street tyres, even if they shitty second hand china specials.

[Jap_star]

went for a drive this morning. doesnt feel at all like surging. must just be the tyres. when i go back for a bit more boost ill change the wheels and see how that goes

[Jap_star]

in the interest on science, and because i love changing turbos, i recently pulled off the 52t .63 rear and put on a 56t .63 rear just to see what the difference was for the turbo coming on, with unsurprising results. The difference seems to be negligible with boost coming on 150rpm earlier back to back. same dyno etc.

next step is to go to a .82 rear and see if that will solve the surge issue. as the .63 really didnt like it when i went e85 and whacked some boost into it

will be doing this next week