Hi-flow turbo= retune?

[whatthe?]

Ok, Ive heard conflicting views about this from people who "heard from someone" or "it was on performance forums' or the like. I'm really after an answer from someone who knows for sure.

My CT26 is away being hi-flowed at the moment. Whilst I will be running the 16PSI maximum that the car was tuned for a couple of weeks ago, obviously the turbo will now be capable of moving more air than it used to. Will the increase in lb/min require retuning? Surely the AFM load points will remain the same (ie: x amount of fuel for y amount of air as read by the AFM and tuned with the SAFC). Are there any other considerations to make?

[30psi 4agte]

I say yes.
Sure your a/F load points may remain the same but the amount of air being moved will be larger and at diff times.
I.E the turbo may now be able to move 200hp worth of air at 4000rpm where as the old one may have only been able to move 150hp worth of air at 4000rpm so this difference needs to be accounted for and factored into the tune.

[oldcorollas]

i say maybe

if it was MAP, then definitely.
but AFM measures the amount of air ingested by engine (as opposed to air not getting in engine), so whilst with MAP, the change in pressure drop across engine due to hiflow (depending on type) will cause issues, with AFM, the AFM will stillmeasure the total amount of air going into engine.

however as 30psi says, you may move into regions of the table that have not been tuned.

i reckon it will be close, but you should dyno it at different loads to check it is ok (which you would do anyway right?).

\/\/\/ nyeh nyeh i agree with ya tho, yes but maybe, but yes to check that make sense?

[30psi 4agte]

Oldcorollas: you beat me to it!!! i was just about to edit my post and say it will be close!!!!
AFMs generally have some leeway but i believe that the high flow will exceed these parameters.

P.s do you no what wheel is going in? if its a T04e or the V- trim youll love it!! they provide a very noticable / good upgrade in power

[4agte]

cant hurt what it cost to tweak one of those things $200 ?

[whatthe?]

It's going back on the dyno for the new power figure anyway, so I'll have them check out the AFRs whilst it's there. Thanks guys

[chris davey]

Good idea.

I wouldn't pay $200 to tune a SAFC though if it has already been tuned. I think that it would be done in 3 runs maximum.

[whatthe?]

I'm sure it wont be that much, the initial tune of ITC and SAFC took 3 hours or more and cost $250. Unigroup is pretty reasonable with pricing

[ra28_miles]

Hi, adding to this, my girlfriends JZX90 shit the tin when the front turbo blew. I was about to put a set of stockies back on when a set of hi flowed ct12s popped up. Since changing over to the new setup boost comes on later, which i knew would happen but the car has gone down on power. Everything is still stock, eg. exhaust, injectors and computer.
I'm looking in a computer and already got 540cc injectors and 255 walbro intank pump for the car.
Just wondering what anybody else running the similar setup has experience.
Cheers
Milesy

[RT40Corona4AGTE]

retune cant be a bad thing. They will be out though i would say. Just check them as you go. I would say that it will probably need tweaking at the least.

[Shifty]

+1 to this.

AFMs cope better than MAP sensing in this situation, BUT your concern is moving into an unmapped area or a mapping region on the table that the ECU can't understand. The AFM might correctly read the airflow, but the ECU may not have a mapping point to correspond with this amount of airflow at a given RPM or load (TPS) point so it could end up off the money because of that.

As you mentioned, chuck her on the dyno and that's the only way to test it safely & know for sure.

i say maybe

if it was MAP, then definitely.
but AFM measures the amount of air ingested by engine (as opposed to air not getting in engine), so whilst with MAP, the change in pressure drop across engine due to hiflow (depending on type) will cause issues, with AFM, the AFM will stillmeasure the total amount of air going into engine.

however as 30psi says, you may move into regions of the table that have not been tuned.

i reckon it will be close, but you should dyno it at different loads to check it is ok (which you would do anyway right?).

\/\/\/ nyeh nyeh i agree with ya tho, yes but maybe, but yes to check that make sense?

[oldcorollas]

if the CT12's were "high flowed" by increase turbine to ex housing gap (flow mroe exhaust) then you should get less boost for a given amount of gas flow.. = less powahs..
depends what sort of highflowing was done

[buzzbomber85gt]

probably just clipping to 12* on turbine. all that really does is decrease the ammount of energy to move the wheel thus causing earlier spin-up and less lag. unless they honed/bored the housing to allow a bigger trim which doesnt really cause less boost....it just creates more lag since it takes more to spin a bigger wheel. regardless your going to have to re-tune if your expecting larger numbers. keep an eye on a/f ratio and boost gauge/shutter

[MWP]

I say no.

ECUs are tuned to for any amount of load (=boost, to a limit) at any point in the RPM range.
Changing to a turbo which spools earlier or later will not effect if the engine then runs leaner/richer with the existing tune.

The only time you will need a re-tune is if you start pushing over the boost that the engine has been tuned for in the past.

[Shifty]

Just to clarify, I'm sure that MWP is talking about AFM'd engines. MAP is different entirely as it doesn't understand that you're flowing more air at the same pressure... while AFM can compensate as it measures air in not pressure.