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Rb25 Turbo And Cam Gear Results

WazR32GTSt

By WazR32GTSt,
in Engines & Forced Induction

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WazR32GTSt Grand Master

WazR32GTSt

Posted
Posted

after a dormant year of mods, have finally done something extra to the ol rb20..

car:

1992 R32 GTSt automatic with 140,000kms

previous mods:

- 3" dump/front

- 2.5" gutted cat

- 3" cat-back

- boost controller 12psi (made same power at 14psi)

- high-flow air filter in stock airbox

- rb26 cams

- some kind of chipped ecu, not sure exactly what has been changed

- FMIC with custom piping

- auto tans cooler

This setup made 132rwkw with 14psi and fairly advanced timing... keep in mind this is an automatic car

new mods:

- rb25 turbo (series 2 with nylon compressor)

- HKS cam gears: inlet and exhaust

- walbro fuel pump

- 3" high-flow cat (note: went from gutted cat to normal cat, so this would have actually robbed some power...)

the narrative:

For the new mods, i Visited the great team at Mercury Motorsport in Newmarket, Brisbane for the installation and tune. They installed the rb25 turbo

and cam gers, and set them at 0 and 0.

The first dyno run was in this state and made 133rwkw with 11psi but was leaning out with AFRs approaching 14. this is when the fuel pump went in...

The next dyno runs were to adust the cam gears and turn the boost up. ended up having 14psi with normal timing and made 154.8rwkw (see attached dyno sheet)

In its final state, the cam gears were set at:

inlet --> +3

exhaust --> -5

as you can see by the dyno graphs, it made a huge improvement than over the standard confiuration. I asked them to set it up for low-to-mid improvement rather than top-end power, which they did.

How it feels to drive:

Down low, is exactly as before with no noticable difference in lag at all. I was quite surprised actually and i put it down to the cam gears bringing boost on earlier and the added mid-range torque.

Up top, it pulls very hard compared to before, and all the way to redline :)

overall summary:

1. making 155rwkw with rb20 automatic

2. very happy with the way the car drives and the increase in power

3. recommend cam gears to anyone that is thinking of this as a future modification

Am open to any advice, comments, or suggestions that anyone might have :P

cheers,

Warren

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https://www.sau.com.au/forums/topic/115398-rb25-turbo-and-cam-gear-results/
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bbe Proficient

bbe

Posted
Posted

hmm did u do a run with the pump 25 and boost set at 14 ? then do another run just with the adjustment only of cam gears ?

cos i have heard many people say gears on the rb20 are a waste of time im just asking not implying

WazR32GTSt Grand Master

WazR32GTSt

Posted
  • Author
Posted
hmm did u do a run with the pump 25 and boost set at 14 ? then do another run just with the adjustment only of cam gears ?

cos i have heard many people say gears on the rb20 are a waste of time im just asking not implying

i wasn't there for the tuning, as i had uni to go to

they did, however do that. that's why the cam gears are set up as they are, because it made an improvement. otherwise they would be left at zero

you'll see when i can get the graph up, its like the graph has been shifted left. i think this was the gears :D

the mechanic actually said that they came out really good and was very happy with the upgrades i had chosen. he said they worked well together..

WazR32GTSt Grand Master

WazR32GTSt

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i want to see the dyno graph :D

is it laggy? i know mine so slow up to around 4000..then it was all on..

drag strip son..

is it laggy?

i can't feel any loss in low-rpm power. not that it had much to begin with, though

definately has power up to 4000rpm.. haven't done a big tester yet so can't say where i hit full boost etc.

actually, on the rb20 turbo, it felt as though it would spool up early, but still wouldn't get moving until it had reached full boost

now, it is ever so fractionally later in spooling, but gets moving as the boost rises so it actually feels the same, if not better in the low-to-mid region

yeah, drag strip will be on the cards. a mid-14 should be achievable i think/i hope.

i think i'll wait for the SAU-QLD drag day in a few months :(

WazR32GTSt Grand Master

WazR32GTSt

Posted
  • Author
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graph has been uploaded finally!

not that this was done in 2nd gear as it is an automaticand that the intake temp is close to air temp which means the results are realistic

(i find that the more the intake temp is above the air temp, the higher the dyno figure is, with about 1deg = 1rwkw)

dangerous_daveo Grand Master

dangerous_daveo

Posted
Posted

First thing, you need to get the ECU re-tuned. I think it will seriously make another improvement, and be well worth the money. That or get another chip that can be tuned. Whatever, just do it.

Reason for saying that. My graph is very very similar to yours (same power as well), just I dont have cams, or an RB25 turbo, or a FMIC. I think with some more tuning, that will be a very smartly modded car, with very good power for the mods.

Either way, thats a pretty good gain for a fairly low outset of money. Just do something with the ECU.

ellie Proficient

ellie

Posted
Posted

What I want to know is = there was a huge thread on fitting RB26 cams in an RB20 with no success, many breakages, cars would only stall for the very few that got them in and with the eventual revelation that you also needed to convert your entire valvetrain to a solid lifter setup! So my question is with now seeing a few people successfully running this setup, how did you get it to work and how did it run?

Cheers in advance!

WazR32GTSt Grand Master

WazR32GTSt

Posted
  • Author
Posted

i didn't do them myself, had them put in by my mechanic. so i don't know how they went in exactly

this thread is about the cam gears and rb25 turbo, so can we keep it on topic? there's already 3 or 4 threads about rb26 cams in rb20

thanks in advance

WazR32GTSt Grand Master

WazR32GTSt

Posted
  • Author
Posted

yeah i wanted to hold off on the pump due to $$ issues, but when they called me saying the AFRs were 13:1 i said go for it..

but well we all know what the next step is going to be :ermm:

i might have to wait for the next QLD visit by Dr Drift...

i'd prefer this to an SAFC which is really my other choice being an automatic

what does everyone think?

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