Boggy Mc Bog

[RaZ_TuRbO]

Ok this is mostly for guys who have rb25 hiflows on there rb20s

I put this turbo on the weekend, everything seems ok, smooth boost throught the rev range and i can feel the difference in top end yadda yadda. But why when i snap it from first to 2nd it just bogs down and has to build boost again, there is no wheelspin. I dont know maybe i was expecting too much.. id like to here others opinons. Mtq hiflowed the turbo.. but s**t it seems real laggy. The only thing i can think of why its laggy is the rb20 elbow is still on there temporarly?

Experiances is all im really after.

Cheers

Raz

[TTT]

list your mods mate.

what else does this car have?

[RaZ_TuRbO]

Supporting mods really,

Full 3" exhuast with open style dump pipe(not split)

Apexi pod

Hks evc

hybrid copy front mount.

safc2

gtr fuel pump

std injector and afm.

made 237rwhp with the std turbo..

Cheers

[R33GOD]

well when you change any turbo in your car. it must be tuned.

when i put my hiflow on it was the same. dont worry about it. tune it and you will see the difference.

post up your results with the MTQ hiflow too. would be interesting to see when its done.

cheers

[bubba]

A standard RB25 turbo on my old 20 was laggy.. a hiflow will be even more so.

+1 get it tuned, they will be able to wind some timing into the offboost areas and get it spooling sooner.

Also, what boost controller are you running if any?

[RaZ_TuRbO]

Its going in next week as my dyno man is currently moving his dyno into his new shop, he said he will sort me out, he is usually right.. lol.

you have an rb25 im guessing? wonder what the rpm difference is usually in comparison to rb20? when were you seeing boost before and after tune.

Cheers

[RaZ_TuRbO]

Bubba its a hks evc.. its old school one but it hold boost fine.

Yeah in thinking he will muck around with the timming and tune it leaner off boost.

[bubba]

Not sure about those controllers, mine has a feature to hold the gate shut till a certain pressure (in my case I have it set to 9psi) which helps spooling.

So you can compare, when I had the standard 25 turbo on my 20 it would start spooling about 2500, make full boost (12psi) by 3500rpm and max power about 6500rpm. That was all untuned.

[discopotato03]

Common problem . What happens is that the engine can now breathe out more easily and will improve its combustion efficiency via better scavanging .

I'd be looking at ways to increase its light load ignition advance whilst maintaining appropriate AFR's .

I went from an RB20 BB turbo to the GT2860Rs on the old FJ20 2L 4 and the extra timing that it could then take was amazing , so were the results .

Cheers , A .

[RaZ_TuRbO]

So disco you say the problem cant really be solved with the rb25 hiflow on the rb20? So the hiflow cant handle the variance in ignition timing as well as a well sorted garrett item?

[paulr33]

might be worth doing the EVC self learn too

that might help with boost build if you find its sucky at the moment

the manual tells how to do it

[RaZ_TuRbO]

paulr33, its an older one just with the knob... nothing technical like the newer ones.

[bubba]

You need to be able to advance the ignition ONLY in the areas where it's not seeing boost anymore, i.e. the stock ecu will be expecting to see a whole bunch of air under pressure between 2000-3000rpm which just isn't there anymore with the bigger turbo.

It's not just a case of turn the CAS to get more advance, you need a custom tune, I had my stock 32 ecu remapped to suit my new engine

[Tangles]

SITC's can help with the ign timing, and bring on boost a bit lower in the rpm

sitc + safc2 isnt a bad mix, add in a z32 afm (seeing you have a highflow turbo, it'll suck way more air in thru the afm) and you can get a good tune going

seeing you have a manual tho, why not get the ECU remapped and then use the safc to simply make minor adjustments to the ROM tune

[TTT]

As above.. SAFC + ITC is for the lazy people with bad knees and can't operate the left foot so drive auto tanks.

sell the SAFC and with the money, you could have a chip for your ecu that will give better results all over the rev range.

The Hi flow RB25 turbo on an RB20 is a pretty common route.

User on here called CEFFIE made 240rwkw @ 19psi on his setup remapping his stock ecu.

And everything looked stock.

have a chat with him

[RaZ_TuRbO]

ITC what is that? safc gives me, ive seen a couple of his posts..ill hit him up.

Cheers.

[TTT]

SAFC is for fuel adjustments.

ITC or SITC is for timing adjustments.

But it's crap.

there are 5 points at which you can make changes (if I recall)

where as a remap can have timing changes at ALOT more points in the rev range.

AND, it is programming the actual computer's own programs rather then "tricking" it via a singal bender like the SAFC is.

[FATAZZ]

your got manual,why not go for a complete aftermarket ecu?

[Sydneykid]

An RB25 high flow (a GCG ball bearing high flow anyway) is not at all laggy on an RB20 once you tune it properly.

Cheers

Gary

[RaZ_TuRbO]

Gary, Its an mtq item and it journal type bearing im lead to belive.