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Quick Turbo Comparison On Rb25

Harey

By Harey,
in Engines & Forced Induction

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Harey Veteran

Harey

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Sooo true. This is only one example from each turbo. I am not sure if the dyno I chose for the HKS 3037 is really doing it justice. Found it on page 25 of the rb25 dyno thread so if you have a better one let me know. I try and find stock engines and roughly 17psi tapering off to around 15.

Birds Grand Master

Birds

Posted
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Wow I'm impressed by the 2835. Very smooth curve, more than enough power for a street car and with basically standard response.

PU makes some impressive midrange power after reaching full boost but the trade off appears to be quite a bit of lag and fade off heading towards upper rpm. As long as you keep within that powerband it looks like a good performer.

As said it's not gospel - we don't know the extent of modification on the cars tested but other than that the general shapes of the curves appear to be pretty accurate.

Granthem Mentor

Granthem

Posted
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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 run the GT-RS... its a pretty good turbo! Makes 253rwkw on 14psi. Lots of other supporting work as well tho. Either way, I think you will be happy with the 3071R. I cant imagine it would be too different in its spool. The GT-RS offers crazy response for the street tho!

Harey Veteran

Harey

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I run the GT-RS... its a pretty good turbo! Makes 253rwkw on 14psi. Lots of other supporting work as well tho. Either way, I think you will be happy with the 3071R. I cant imagine it would be too different in its spool. The GT-RS offers crazy response for the street tho!

Post up (or link) your dyno and I will add it in to the chart.

Granthem Mentor

Granthem

Posted
Posted
Post up (or link) your dyno and I will add it in to the chart.

Take your pic as to which one. without over laying them I think they are pretty close for two different dynos :cool:

Keep in mind this car has HKS cams which should increase midrange (plazmaman plenum, some head porting). For that reason its up to you whether you add it or not, considering you are looking more towards stock engine turbo upgrade comparisons? :P

post-41581-1270011897_thumb.jpg

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Sheriff Wan Proficient

Sheriff Wan

Posted
Posted

Hey good idea.

I use Excel quite a bit - so i knocked up one of the ones Ash was talking about where you tick the box and it adds/removes the item,

Feel free to use this one if its easier & If it can be uploaded into SAU go for it - if not - don't worr about it :cool:

I know its not a common one but I'll post up my RB25 with HKS 2530 when I get the new Dyno sheet.

Cheers,

Disregard the numbers - they are all made up!

SAU_Turbo_Chart.xls

Granthem Mentor

Granthem

Posted
Posted
Ok HKS GTRS added

Interesting granthem your dyno finishes around 175kph or 6200rpm. What happens after that? Just flat?

Nope, thats my limiter! (thats actually my car reving to 7200rpm in 4th gear on both dyno runs). Dont ask me why, but its got short ass gearing. Maybe it has shorter diff gears then the standard 4.11s, or the actual gearbox has different gearing (I think it might have some straight cut gears, whines like a bitch)

Either way, thats all the way to limiter (7200rpm) in 4th on both runs. Something aint stock :P

What exhaust housing are you running Granthem?

Unknown dump, RSR 3.5 front and 3.5 from the cat back from memory. Still running a cat too, but its getting on now and is cracked and shitty. Still, pulling ok figures i guess

hypergear Grand Master

hypergear

Posted
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With the 2x PU highflowed curves tipping off this is due to the stock actuator been too soft. (didn't have high pressure actuators and wastegate controller back then). They are capable of making lot more power then that at full potential.

Also please try to map kwickr33's ATR43G4 dyno reading. I believe that is a very interesting read out.

Lithium Grand Master

Lithium

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Shame there isn't a dyno plot of the GT3076R showing its full strength in there - you see the slight compromise in low down over the GT2835, and not the top end roar.

Fwiw, GT3037 and GT3076R are exactly the same - so really you could just stipulate "GT3037/GT3076R - .xxa/r" as the a/r bit is going to be the only thing which changes the spool and top end flow.

Lithium Grand Master

Lithium

Posted
Posted

Don Dada - btw, slightly OT threw the Skyline for a power run at a local car event just to test the cars behaviour and determine if its ready for tuning. The internal gate is still a little lazy compared to an external but far better than before, hits 1bar by 3600ishrpm then eases off its aggression in spool (wastegate easing open) to hit 17psi by just over 4000rpm - where it holds flat enough to redline that it could have been done with a pencil and a ruler.

Power figure inconsequential at this point, fat as hell fuelling at that boost level as its not been tuned to do anything other than not pop - hopefully will be sorted very shortly now I know its all good to go... then I might be able to add a revised IG GT30R result :D

Harey Veteran

Harey

Posted
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With the 2x PU highflowed curves tipping off this is due to the stock actuator been too soft. (didn't have high pressure actuators and wastegate controller back then). They are capable of making lot more power then that at full potential.

Also please try to map kwickr33's ATR43G4 dyno reading. I believe that is a very interesting read out.

Well post up the revised PU high flow on a stock engine and show us.

I am hesitant to post up kwickr33s dyno as he has worked heads, therefore not being equal to the other dynos.

Harey Veteran

Harey

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Posted (edited)
Shame there isn't a dyno plot of the GT3076R showing its full strength in there - you see the slight compromise in low down over the GT2835, and not the top end roar.

Post one up then. I just chose the first one I could find in the dyno thread that had a stock engine and looked like it was running well.

Edited by Harey
Harey Veteran

Harey

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Ok now with Hypergear ATR3G4 and updated HKS GTRS. For both of these dynos they hit the rev limiter just after 170kph which earlier than what the other cars here are doing. I have modified the speed per rpm for these two and set 7000rpm = 170kph. They both seem to be have very low power down low which doesnt seem right. Dynosheets with rpm are much preferred. rpm per speed seems to vary quite a bit between cars ??

post-29432-1270084535_thumb.jpg

Granthem Mentor

Granthem

Posted
Posted

Hmmm yeh mine does look pretty poor down low. A comparable car to mine is PM-R33, and he has dyno graphs lying around here somewhere I think. It ended up with around 263rwkw on 20psi i think.

Still, I always thought my gearing was shorter, and now i know it is!

Granthem Mentor

Granthem

Posted
Posted

Hmmm yeh mine does look pretty poor down low. A comparable car to mine is PM-R33, and he has dyno graphs lying around here somewhere I think. It ended up with around 263rwkw on 20psi i think.

Still, I always thought my gearing was shorter, and now i know it is!

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