rb20det step by step

[alexj]

Thought I'd post up the dyno plots I've had from the abbey dyno days we've had over the years. they show my RB20DET powered HCR32 from a stock auto 170bhp ath upto its current state of tune 233bhp ath.

First 2003 Stock Auto

Something crazy with the torque here due to the dyno not knowing what to make of the auto i guess. Fresh off the boat and a healthy 172bhp



Again with the mad torque - but this one shows the stock fueling pretty well, shows how lean they run low down before we start adding exhausts and upping the boost and they go all rich



stock rb20det boost of 0.8 bar falling to 0.6 at peak power - lets be honest its a little limp

[alexj]

Next 2004

Still an auto, but now with R34 GTT wing mount IC, Bren Device set to 0.9bar, humungous Apexi Hyabusa exhaust, an Abbey decat and an Apexi SAFC II tuned expertly by yours-truely

Hello 209bhp ath - thats a bit better, torque reading's still all over the shop obviously lol


I think the torque on this one may be accurate - still running well rich due to my conservative SAFC tuning, in reality i think the AFRs where smoother than this but the dyno sensor was a little worse for wear.


Bren device doing its thing peaking at 0.9 bar dropping much less than before to just under 0.8bar - who says you need electronic boost controllers

[alexj]

Finally 2006

Added Blitz Dual SBC S, an ichy mingy FMIC, 3inch SS Downpipe and leaned the SAFC up a bit more - oh and a manual gearbox.

Bong 233bhp ath


New fangled EBC holds the boost just like the old Bren Device


This time Dan and I did some geek techy bonding and he downloaded all the raw data in xl for me - shows my much better effort at tuning the SAFC this time.

[alexj]

something one of you bright sparks might like to help me with is why the peak power is slowly coming down the RPM

2003 6700rpm
2004 6200rpm
2006 5500rpm

whys that then?

[Andy W]

electronic are always better Alex, but if you're getting the results you're after who am i to say different

it's about time for another day on the dynopacks, i'll give Mark a bell on monday and see what dates are available

[alexj]

i was hoping someone would suggest that - judging by the dates on all these dyno sheets - looks like november is the traditional month

i've got to get my arse in gear - i've got 370cc injectors and a RB25DET Turbo to fit and the ROM to edit to match yet.

[alexj]

still amazed how lean the stock fueling is - at peak boost like 3000rpm stock fueling was 13.5AFR - on the 2006 plot its like 11.5 , though back then I hadn't made any adjustments on the SAFC below 3000 RPM as i was under the impression that there wasn't any point - have since learnt different...

also you can see how much later its making boost (at the manifold) in 2003 spec vs 2006 spec (i think the 2004 boost plot is a red hearing as the pull doesnt really start until past the point it should already be making full boost), like at least 500rpm later - spose it could either be the FMIC vs the WMIC OR the MBC vs the EBC ....

[Ahapartridge]

Originally Posted by alexj

something one of you bright sparks might like to help me with is why the peak power is slowly coming down the RPM

2003 6700rpm
2004 6200rpm
2006 5500rpm

whys that then?

I think pushing more boost through the std turbo exhaust housing could be a contributing factor, it will be interesting to see how the 33 unit fairs.

The RB20 does take well to the sort of mods you have done but you are now going to get to a point where after the 33 turbo has been fitted any other increases will probably mean lag.

I am pretty sure the std RB26 cams fit in and offer some gains, those along with some adjustable pulleys could be a good move maybe?

[alexj]

Originally Posted by Ahapartridge

I think pushing more boost through the std turbo exhaust housing could be a contributing factor, it will be interesting to see how the 33 unit fairs.

The RB20 does take well to the sort of mods you have done but you are now going to get to a point where after the 33 turbo has been fitted any other increases will probably mean lag.

the r32 and r33 are surprisingly close in spec, the exhaust sides are almost the same. so i'm not expecting miracles and like you say more lag is on the cards even with the r33 unit. if i decide to go much further i'd probably get my old rb20det unit hybrided to something like a gt28rs/hks2530 spec so i can run more boost, say upto 1.2 bar since rb20det internals are sposed to be able to take it. some guys on SAU have got some good results

Originally Posted by Ahapartridge

I am pretty sure the std RB26 cams fit in and offer some gains, those along with some adjustable pulleys could be a good move maybe?

cams are pretty cheap so i'd probably go with some medium poncams or sumat and i remember a post on SO back in the day, from gtstlad, i think, with some dyno plots showing a decent (7bhp or whatever) gain from just adjusting the cam timing very slightly on the rb20det