Rb25 Dyno Results Summary

[M@&k]

Hi all,

Have pulled together some info from the RB25 dyno results thread. Only considered some of the more common turbo options (for more data points), and have focussed on those which are internally gated.

Turbos looked at were:

• HKS GT-RS
  
• HKS 2835 Pro S
  
• Hypergear SS1PU
  
• GT3071
  

Was originally going to do 3076 as well, but didn't find a whole heap of examples where internal gate was still used.

Have put together two plots. One shows peak power vs boost, and the other shows some dyno curves. Dyno curves are approximate, as I only read off a handful of points from

posted images. Also recorded a bunch of dyno curves in km/hr but cbf trying to convert as not aware of different drive ratios between RB25 variants (e.g. Stag vs Skyline).

Might dig some more in the info later to see if any other trends (e.g. for intercooler types), but nothing was immediately obvious.

Some observations from myself:

• You're not going to see benefits of the bigger turbos (e.g. 3071) unless you push higher than 16 psi.
  
• Those with cams seem to be consistently at the top of the range. i.e. cams are good.
  
• Best results were had with Neo engines, but also some strangely poor results with GT-RS.
  
• SS1PU looks very good, shame there wasn't more results.
  
• Strongest mid range from 2835 Pro S
  

Some possible conclusions:

• If you only want to run 16psi, stick with GT-RS (GT28) sized turbos.
  
• If you want max mid range (3-5,000rpm) smaller turbine is better.
  
• GT3071 really shines > 5,000 rpm, and needs boost.
  

No groundbreaking insights here. There's obviously a heap of other factors that come into play too, but hopefully is of some interest.

[Ben C34]

What housings are used?

[hypergear]

Pretty interested to see where the SS2/3 alpha turbos stands. You can get data from our site:

They are on stock cams.

http://www.hypergearturbos.com/atr43alpha.html

[M@&k]

What housings are used?

Housings weren't always specified. But for HKS and SS1PU turbos I believe they generally only come with one option.

For the GT3071 I expect they were mostly 0.82 AR housings. The exceptions are:

• the Neo with 301kW @ 17psi which used a 0.63 AR (one of the top 3071 results)
• the one with the AVO housing (noted on the graph)
• one with 234kW @ 15psi which has a "modified R33" housing.

Pretty interested to see where the SS2/3 alpha turbos stands. You can get data from our site:

They are on stock cams.

http://www.hypergearturbos.com/atr43alpha.html

Stao, I will look at adding these.

To try and keep things comparable, I was only looking at turbos mounted to the stock manifold, which ruled out your results unfortunately. Might look at a different plot for high mount results...

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EDIT: *** NOTE - THINGS MISSING FROM ORIGINAL POST ***

Results looked at were limited to the following:

• Stock exhaust manifold
• 98 pump fuel only

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Edited November 13, 2013 by M@&k

[Lithium]

Not mentioning what fuel and/or injection makes it hard to know what to make of those results