Quick Turbo Comparison On Rb25

[Harey]

Hi All,

I have been looking at lots of different turbos that would work well on my RB25. So I had a few minutes spare at work and thought I would put them on a chart to do a comparison. Let me stress this is very approximate, I only took 7 different rpm readings and rounded off the power figures to at least 5kw. Its just more to get an idea of the different shapes etc.

- 3071R dyno sheet was obtained from the Nistune Forum, in particular Matts own one

- 3076R dyno sheet was obtained from the RB25 dyno results thread on this forum

- Hiflow was off Hypergears website

- PU Hiflow was also off Hypergears website

- Std Turbo is my own dyno sheet

Some of the inconsistencies:

- boost level, generally it is around 17psi dropping off to around 15psi (except for the std turbo which is only 10psi).

- speed vs rpm seemed to vary between the dyno sheets, could be the different model cars having different diff gears.

So please take it for what it is.

[75coupe]

so how about seeing the HKS 2835 ProS or the HKS 3037 on there...

how many power curves can you fit on there before it becomes hard to read.

[Harey]

so how about seeing the HKS 2835 ProS or the HKS 3037 on there...

how many power curves can you fit on there before it becomes hard to read.

they are out of my budget so guess I hadnt even been thinking about them. will see if i get some more "spare" time at work hehe

[Harey]

As requested:

Now with HKS 2835 and 3037 Pro S

Edited March 30, 2010 by Harey

[kwickr33]

put my ATR43G4 graph with worked head in

http://digi-hardware.com/images/dynosheets...wkwsrb25det.jpg

[Harey]

Anyone got the speed per rpm calculator? Is it different between 33 and 34s?

[R31Nismoid]

Can you also start @ 2000rpm?

Fussy i know, but a fair bit of driving is between 2000-3000rpm for a lot of people, IMO it's an area that can be important.

Larger turbo you have, more of a "hole" you have before 3000rpm meaning around town the car tends to feel lazy.

Which result of 3071 did you use? Perhaps try one of the ones from this forum?

The 3071 seems to be a bit slower than i'd expect...

I'll have a chat to Paul and Christian and see if we can't get our own version going - one similar to anti-lag's where you can remove graphs and add them in at will.

Will take someone to manually plot them i think, but once initial work is done could prove quite handy overall.

[kwickr33]

Ratio seems to be 1KMH : 37RPM

[paulr33]

sau.garagespank.com dyno thingy was the old tool we used

RPM = (SPEED / 28) * 1000

this assumes 4th gear with 4.11 diff gears

so for BNR34 it should be dynoed in 5th gear, HR32,ECR33, BCNR33 all 4th gear

[75coupe]

oh cool I made the right choice with the 2835 then with the earlier power range, which is what Im after.... I cant wait...

but geez the 3076 really does have some mid range doesnt it... oh well...

thanks btw..

[chrisR34GTT]

Great idea Harvey. I am freaking out about my turbo selection now, I went and bought a 3071R (real spec) in 0.63A/R, but I keep being told that I should have gone with a 2871R instead for chasing a responsive 250-260kw? Is there any way to add a 2871R (HKS GT-RS) to the chart, just for comparison? And maybe show the exhaust A/R to legend?

Thanks mate!

[Tangles]

3071r with .63a/r should be bang smack on 250-260kw

3076r with .73a/r should be around 280kw

plenty of midrange pull with both these above, 3071r > 2871r imo for RB25

[Harey]

Can you also start @ 2000rpm?

Fussy i know, but a fair bit of driving is between 2000-3000rpm for a lot of people, IMO it's an area that can be important.

Larger turbo you have, more of a "hole" you have before 3000rpm meaning around town the car tends to feel lazy.

Which result of 3071 did you use? Perhaps try one of the ones from this forum?

The 3071 seems to be a bit slower than i'd expect...

I'll have a chat to Paul and Christian and see if we can't get our own version going - one similar to anti-lag's where you can remove graphs and add them in at will.

Will take someone to manually plot them i think, but once initial work is done could prove quite handy overall.

Yup will try and get some 2000rpm readings.

I got the 3071R chart from here:

http://forum.nistune.com/viewtopic.php?f=2...fa&start=15

Its really hard to compare apples with apples as I mentioned with different boost levels and other differing setups.

I reckon the really surprising result is the PU High Flow offered from Hypergear!

All turbos (except standard and std hi flow) have a 0.82 equivalent size exhaust housing. Im a mid range top end person so thats what I naturally focussed on. In my opinion you want to make sure a turbo makes power all the way to redline, no point having a such a nice revvy engine like the rb and then a restrictive turbo. Yes there are plenty of turbos that can still have some nice low down as well which is the ideal of course. If low down torque is your number 1 preference then why buy an rb25, plenty of other larger capacity engines with more low down torque. I agree though its about the overall package.

Yeah would be great to get a more detailed one going. I have always found it hard to look at different dynos and compare them.

Edited March 30, 2010 by Harey

[Harey]

Great idea Harvey. I am freaking out about my turbo selection now, I went and bought a 3071R (real spec) in 0.63A/R, but I keep being told that I should have gone with a 2871R instead for chasing a responsive 250-260kw? Is there any way to add a 2871R (HKS GT-RS) to the chart, just for comparison? And maybe show the exhaust A/R to legend?

Thanks mate!

I think you have chosen well with the 3071R. I think a 2871R is too small for an rb25. I would actually choose the 0.82 housing with the 3071R but thats just me. I think the 3071R has the nicest curve (excluding the hks turbos) on that chart.

[chrisR34GTT]

Do you know what A/R Matt has on his 3071? From what I have read boost control seems inevitable with the 0.63, but I just don't know what the lag would be like for the 0.82. However, if confirmed that Matt has 0.82 then I will gladly swap over as the 3071 curve follows a similiar progression to his stock turbo setup.

[chrisR34GTT]

Yup will try and get some 2000rpm readings.

I got the 3071R chart from here:

http://forum.nistune.com/viewtopic.php?f=2...fa&start=15

Its really hard to compare apples with apples as I mentioned with different boost levels and other differing setups.

I reckon the really surprising result is the PU High Flow offered from Hypergear!

All turbos (except standard and std hi flow) have a 0.82 equivalent size exhaust housing. Im a mid range top end person so thats what I naturally focussed on. In my opinion you want to make sure a turbo makes power all the way to redline, no point having a such a nice revvy engine like the rb and then a restrictive turbo. Yes there are plenty of turbos that can still have some nice low down as well which is the ideal of course. If low down torque is your number 1 preference then why buy an rb25, plenty of other larger capacity engines with more low down torque. I agree though its about the overall package.

Yeah would be great to get a more detailed one going. I have always found it hard to look at different dynos and compare them.

Didn't see that.

Well in the name of ressearch, to compare apples with apples, is there anyone out there with a reasonably priced genuine 0.82 exhaust housing that they could sell me? I could do dyno runs with both setups (3071R 0.63 & 3071R 0.82) at the same boost levels and post them up. Anyone interested to see that?

[Harey]

Didn't see that.

Well in the name of ressearch, to compare apples with apples, is there anyone out there with a reasonably priced genuine 0.82 exhaust housing that they could sell me? I could do dyno runs with both setups (3071R 0.63 & 3071R 0.82) at the same boost levels and post them up. Anyone interested to see that?

Hells yes I am interested

Fair effort for you though.

[Harey]

Ok heres one from 2000rpm also with exhaust housings mentioned. The HKS 3037 dynosheet starts at 100km/h so no info below then, so I just left it out.

Edited March 31, 2010 by Harey

[Harey]

oh cool I made the right choice with the 2835 then with the earlier power range, which is what Im after.... I cant wait...

but geez the 3076 really does have some mid range doesnt it... oh well...

thanks btw..

Personally I the HKS 2835 is the choice off all those turbos. I would be very content if I were you.

[tridentt150v]

Interesting........the 3076 obviously is not on the best combination of motor/mods otherwise is would continue to go up the chart rather than dip and turn over.

The 3037 is a really good progressive turbo, but has less midrange than I thought it should have, but as you say they are all 'snapshots' of one! Ohh to be able to have the time to take a sample of say 20 for each turbo and then plot the average. Never mind in a braod sense it is all relative.