Precision Billet Turbos

[SiR_RB]

I noticed the new 7275 and 6875 doesn’t have a T4 divided rear option

only Vband rear and T4 open

 

can anyone see any issue with running a twin scroll T4 divided manifold with twin gates into an open T4 rear ?

[Lithium]

13 hours ago, SiR_RB said:

can anyone see any issue with running a twin scroll T4 divided manifold with twin gates into an open T4 rear ?

No, I really can't see an issue with it.   The merge may not be perfect but there are definitely worse ways of doing it - it could arguably work nicer than some 6>1 manifolds out there.

[feedmyfast]

21 hours ago, Lithium said:

Ha! That is ridiculous, nice work!  That's gotta be one of the more stout RB25 setups out there, being SAU people will probably make dyno comments but realistically - an RB25 with 270deg cams and 40psi pumped through it on E85 is going to make some serious power

What is the spool like?  There is no rpm scale on the dyno plot (NFI why people print plots like that), so a bit hard to tell.   Be very interesting to see how it goes at the strip, hope you have a decent trans!

 

spools insanely quick. that ramp up is within 1000 RPM. It takes off like a rocket. I roll race so I needed the snappy response.

 

On 7/31/2019 at 1:30 AM, Dale FZ1 said:

What turbine housing size - also single/split pulse + gate setup?

Perhaps drop something into the RB25 dyno results page

Strong result.

single pulse, 44mm wastegate , T4  - 81 AR

[r33ryan]

11 hours ago, feedmyfast said:

spools insanely quick. that ramp up is within 1000 RPM. It takes off like a rocket. I roll race so I needed the snappy response.

 

single pulse, 44mm wastegate , T4  - 81 AR

Would love to compare it to my rb25 6062 setup in terms of response.  

QLD or Syd roll racing?

 

Also curious on what headstuds youre using? 

Edited August 2, 2019 by r33ryan

[SiR_RB]

Anyone got any results from the newish 7275 or 6875 turbos yet?

 

or do I have to be a first and report how it goes lol

[klutched]

I've just found out that the "7675" I thought I had was actually a 7175 rated to 985hp. Explains why it was so responsive and why my IATs were so high on high boost ? 

The 7275 Gen 2 should be a pretty stout turbo considering its rated at 1200hp and biggest housing offered is a .96 which should mean it will possibly spool a bit quicker than my 1.12 7175?

Mine started to max out low 30s so im not sure how well matched the compressor is to the turbine but the newer wheel might make it better.

I've now upgraded to a 7685 so we'll see how that goes. Will report back once shes up and running again.

[Lithium]

3 minutes ago, klutched said:

I've just found out that the "7675" I thought I had was actually a 7175 rated to 985hp. Explains why it was so responsive and why my IATs were so high on high boost ? 

The 7275 Gen 2 should be a pretty stout turbo considering its rated at 1200hp and biggest housing offered is a .96 which should mean it will possibly spool a bit quicker than my 1.12 7175?

Mine started to max out low 30s so im not sure how well matched the compressor is to the turbine but the newer wheel might make it better.

I've now upgraded to a 7685 so we'll see how that goes. Will report back once shes up and running again.

What did you make with the "7675" again?

[klutched]

8 hours ago, Lithium said:

What did you make with the "7675" again?

1021hp 1374nm 35psi 

[SiR_RB]

10 minutes ago, klutched said:

1021hp 1374nm 35psi 

What engine was that on ?

 

 

[r32-25t]

14 hours ago, SiR_RB said:

Anyone got any results from the newish 7275 or 6875 turbos yet?

 

or do I have to be a first and report how it goes lol

I get the feeling you’re going to be the guinea pig  

[Dose Pipe Sutututu]

4 hours ago, SiR_RB said:

What engine was that on ?

 

 

He has a built 3.4L, still holds Australia's fastest R33 S2 GTS-t WITH sunroof @klutched lol

[SiR_RB]

Lol

[klutched]

Yep built 3.4 with a fairly big 26 head, no gas and through glide.

[Taha]

21 hours ago, SiR_RB said:

Anyone got any results from the newish 7275 or 6875 turbos yet?

 

or do I have to be a first and report how it goes lol

Hi what engine is it going  on

[SiR_RB]

High compression 2.8 with cnc ported head 

[Lithium]

23 hours ago, klutched said:

1021hp 1374nm 35psi 

That's pretty impressive, all things considered!  The actual 7685 will make things rather interesting

[SiR_RB]

If anyone is selling their precision let me know please

after something from 6875 to 7675 in size 

T4 rear

 

thanks 

[meX]

Good afternoon Volks,
please let me grab out this old topic and try to get some experienced answers from your side for my little problem i got.
Engine is a Stock RB26 with metal head gasket and stuff (stock bottom end) except HKS 272 degrees camshafts and on that is sitting a PT 6466 CEA Gen2 TwinScroll with a VBand 0.82 A/R outlet (1 Wastegate).

In sum, im actually pretty unhappy with the spool and the driving style. I've got at around 612 HP @18 PSI but the spool at ca. 5,5K rpm is horrible for street drives. The car runs on petrol with 100 octan (E85 is not possible here, no gas stations available hard to organize etc.).

The problem i got is the bad spool and responsivness of the car. It is generally driven on the streets and in the hills, where i need a fast spool and good power band more than everything else and after driving in corners, with this kind of spool, it's feeling like that you shift everytime in a big nowhere.

Now i want to come back to my question. Im thinking about a setup change/switch but im not pretty sure, which is maybe the best solution and therefore I want to please you with some experiences.
The first option would be to get another Single from Precision which may fits on the actual Manifold etc. or go back to like Twin Setup  HKS GT-SS with a good spool but than, i have to change from the single setup (manifold etc.) to the twin.

Are there people here which may have experiences with a PT 5862 or a PT 5858 on 100 Octans for this application? I see some dyno sheets here but the most were done on E85, which is not comparable to the 100octans. I think that it's maybe also possible to just switch the turbo, until the Stroker is done and the head ported. But im still struggling, if this brings the final aim, that i have with the responsivness

The Aim is to get >600 horses at the engine on 100 octans, but the most important is a good responsivness with a good power band.

Friends of mine are driving those 2860-5 and HKS GT-SS Turbos in their r32 gtr's, on the same base and compared to their quick spool, they are completely different cars, but in the street and for some open time track days, it makes even more fun to drive with them.

If there's someone who can help, it would be great.

Thank you guys and stay safe

Edited April 12, 2020 by meX

[r32-25t]

A .82 rear housing is an open scroll turbine housing you need the .84 twin scroll one on a twin scroll manifold. i have a 6466 .84ts on my stock bottom end 2.6 and mine is all in at 4,100rpm

[KiwiRS4T]

My first suggestion would be to tone down the cams. Even to stock cams or some custom cams with less overlap but higher than stock lift (with some adjustable gears to get the optimum settings). So far as I can see aggressive cams are for engines operated principally at high revs...drag cars or circuit racers with a close ratio box.

Secondly  to convince you that going back to twins would be a retrograde step have a look at this video - it is definitely worth a watch: :http://www.goodezilla.com/rb26dett-skyline-gtr-single-turbo-vs-twin-turbo

Regarding turbo choice I have no advice for you - my experience runs only to an old school GT3540R. It could be that your turbo could be adapted but I will leave it to those with better knowledge than I have.