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Heya guys,

I picked up my new pride and joy on saturday and im loving it so far, alltho my mate took me for another run in his HR31 with RB20 red top and it is a SHIT LOAD quicker than mine and i cant work out why.

here are my specs

RB20 silvertop ECCS

Rb25 T3 turbo on 14psi

HKS cooler (600x300 ish with was looks to be 2.5" piping.

2.5" downpipe off turbo into a 3" system with two mid mufflers and a rear muffler (5zigen system) (no cat)

standard wastegate and factory bov

turbosmart controller (it is mounted on teh firewall, should it be that far away from teh turbo and the actuator?)

SAFC2 (not sure on how it has been tuned, wether on dyno or in driveway by previous owned)

normal GTST box and LSD diff with coilies and a massive pressure clutch, really bites :P

my mates mods

HR31 redtop RB20

Rb25 T3 turbo on 1 bar

600x300 cooler (unsure of brand)

3" system straight to a rear muffler with Apexi exhaust valve

HKS BOV and some electronic valve control thingo

bee*r

apexi Neo AFC (tuned for about 250hp aparently)

5 speed manual and lsd

we are both running exactly the same width tyres.

(its [THN] s old car (tuyen)

basically his scares the shite out of me, really gets up and boogies and it just pulls harder every gear however mine feels like it has 40hp less or more and splutters around 5K and is i feel it is slower than my 4agze running 13psi.

seeing we both run very similar gear i would expect mine should be a bit faster due to it being a Silvertop, but nooo

could i have a shitty tune on the afc? i just dont get it :thumbsup: i want mine to be as fast.

Edited by YEHBOI
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thats why i thort i may have a shitty tune :S i used BP ultimate too.

im not overly sure but with me on my own it isnt even as fast, with both of us in his car which is an extra 80kgs his is still faster. both of them are kept pretty well factory sort of weight. (he doesnt have weight reduction or anything like that)

Edited by YEHBOI

Other than the obvious misfire you have, i'd suggest you have a more restrictive exhaust, and your mates car has a bit of tuning where yours doesn't. Then theres the fairly general term of "T3 turbo". Seriously it could be anything with a t3 flange on it.

  • 3 weeks later...

Obviously there could be many things as to why your car is not as fast. But it comes across as if you assume the silvertop "should" be faster.

The silver came out when all the emissions crap was going on etc. It had a BOV where the red didnt have to. Dont quote me but I think the eccs redtops were also cammed differently i.e more aggresively.

The redtop could of been freshend up in its lifetime where your silver could be on its last legs etc etc etc.

The ex gibson GTSR's run redtops and go just fine lol.

I thought the limit for the 33 turbo was 14.5 pounds??

any idea what a set of coils will be? i have a feeling im not going to get much change out of 2K for a set of brand new ones

Since you are running it on an rb20 you should be able to run 16-18 pounds safely, on the RB25 it's limit is around 1bar, depending on the wheel specs, as long as you have the ceramic and not the nylon wheel, you'll be fine

coils are quite expensive, you might only have one or two bad ones, you can get second handers quite cheap, or go for a wasted spark setup using VL coils and I used VN leads, works fine :( total cost was $140-160, or you could go splitfire for round $500

As for the spluttering, I think it does sound like an incorrect tune on the SAFC

You should:

Crank the boost

Get it tuned

Replace any coils if need be

Don't tell your mate :P

Also if you are running the standard dumppipe you might be restricting the flow, you could always opt for a 3"incher to the cat or a 2.5" with a seperate wastegate elbow which joins up somewhere down the front pipe

What sort of cat are you running? i've you've only got a catback exhaust with standard cat, you won't be gaining the full potential of your exhaust, I suggest if it's all stock, replace it with a higher flowing cat, or if it's legal in your state - rip it out :thumbsup: I've done that to all my cars here in NZ

Since you are running it on an rb20 you should be able to run 16-18 pounds safely, on the RB25 it's limit is around 1bar, depending on the wheel specs, as long as you have the ceramic and not the nylon wheel, you'll be fine

sorry champ there is a fair bit wrong with this statement, just thought i would clear a few things up...

1. On an RB25 with RB25 turbo you can run 12psi or on an RB20 with an Rb25 turbo you can run 14psi. no higher

2. In regards to the wheels. All RBXX turbos have ceramic turbine wheels. the difference is in the compressor wheel. RB20, series 1 RB25 run alloy iconnel wheels. series 2 RB25 turbos and Neos run nylon compressor wheels. there turbos are limited to around 12psi because the hugher shaft speed required for 14psi is enough to start delamination.

so the clear things up run an absolute max of 14psi. 12 would be safer.

cheers!

id say the spluttering would be coils, get a set of split fires as already suggested, get a 3" dump and you have way to many mufflers in your exhaust. id get a good high flow cat and get the 2 mid mufflers taken out. or forget the cat and still get the two mid mufflers removed.

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