If I get a turbo back exhaust with a downpipe and test pipe with a K&N or Apexi Intake will it run too lean for the stock engine management to control?:1zhelp:
Will it run too lean?
- Thread starter JDMSupra
- Start date
yes i know its fuel injected and im not that stupid. i was just wondering if the stock computer would be able to adapt to the new air flow well enough for the EFI to work at peak efficiency. please be patient with me, i've tried searching and im very new at thissss.
It'll be just fine...that's a good start to the upgrade path. When you start putting more air into the motor (more boost like Red Dragon said) or go the Lex AFM route, that's when you need to up the fuel via bigger injectors, fuel pump, FPR.
How much approx. will I be boosting? And I have heard about this fuel cut problem could someone explain it to me in a nutshell?
depends on the DP. if its just a regular ol 3" dp id say you will be in the neighborhood of 10 psi (just a guess) i beleive BIC said with his DDP you will be making like 13 psi. cant tell you for sure as my car has a crazy boos leak when i put my DP on and had a boost controller at 10 psi after i fixed the leak.
fuel cut aint much more than your ecu reading to much boost/air moving past the afm. it then pretty much cuts the motor out for a second to stop it from overboosting.
a buddy of mine was running the cooleze DP and blitz nur catback and wasnt hitting fuel cut. its not too much money to get a mechanical boost guage and mechanical boost controller. that is a good next step to make sure you stay at a safe boost level. :icon_bigg
fuel cut aint much more than your ecu reading to much boost/air moving past the afm. it then pretty much cuts the motor out for a second to stop it from overboosting.
a buddy of mine was running the cooleze DP and blitz nur catback and wasnt hitting fuel cut. its not too much money to get a mechanical boost guage and mechanical boost controller. that is a good next step to make sure you stay at a safe boost level. :icon_bigg
Fuel cut occurs when the stock ECU senses an "over boost". It varies with a stock set-up like yours, but somewhere around 10-12 psi (easily done by shimming the turbo waste gate) the ECU will basically cut the gas off to the injectors. There's no doubt when it occurs...really gets your attention.
The Lex AFM/550 combo is one way to fool the ECU and up fuel cut to around the 16-18 psi range. You'll need a boost controller to keep it less than that or you will have a hard time getting consistant full throttle. You will also need a way to control fuel to match up to your boost curve to make sure you don't lean out or experience detonation...both are very bad on this motor.
There are several ways to crack the fuel cut nut :naughty:
Hope it makes sense...this is kinda in a nut shell...do a search and read up on it and how to get around it.
The Lex AFM/550 combo is one way to fool the ECU and up fuel cut to around the 16-18 psi range. You'll need a boost controller to keep it less than that or you will have a hard time getting consistant full throttle. You will also need a way to control fuel to match up to your boost curve to make sure you don't lean out or experience detonation...both are very bad on this motor.
There are several ways to crack the fuel cut nut :naughty:
Hope it makes sense...this is kinda in a nut shell...do a search and read up on it and how to get around it.
so with those mods, the amount of boost i will be running is considered safe for the motor or no?
It's definetly safe. Your freeing up the exhaust and helping the turbo breath alot better that's why the boost increases, but it won't damage anything with the natural increase in power. The fuel cut is there to really help you, when it senses you might be close to damaging anything it stops before you can. It's toyota's way of protecting the engine from people upping the boost without proper fuel. You probably will be under fuel cut with those mods, If you got a Manual boost controller and upped the boost some more you might hit it, but again it's protecting the engine so you don't run lean, just back the boost off alittle and you'll be set.
and watch that headgasket :icon_bigg
you should be fine. just invest in a boost guage and controller soon.
you should be fine. just invest in a boost guage and controller soon.
^^:werd: Next investment should be a boost gauge because your stock gauge is slow, innacurate, and useless over 8psi
And if you haven't yet, do a search on Headgasket and spend as much time as you can researching that. If you're serious about boosting and upgrading this is gonna need to be one of the first things tended to.
And if you haven't yet, do a search on Headgasket and spend as much time as you can researching that. If you're serious about boosting and upgrading this is gonna need to be one of the first things tended to.
lol thats another thing, i have read a lot about the supras tendency to pop head gaskets every so often. for the MHG what thickness should I get. Still the stock one in there so 1.2 mm?
The thickness depends on how much needs to be shaved off your block and head, You can go with a stock gasket and torque to 75+ft.lb. The main reason for the stock gasket to blow so easy is because it was torque'd so low from the factory. Many people replacing with stock gasket and torqueing properly have had good luck as long as you don't go crazy with boosting. I heard of someone running a 60-1 trim CT26 pushing around 450 hp on a replacement toyota gasket. It's much too late to remember the details, but he said when done correctly the stock gasket can handle what the CT26 throws at it. How much do you plan on modding? with big goals in mind you might as well upgrade to MHG now instead of tearing it off again.
for engine mods probably just exhaust, down pipe, test pipe, intake and blow off valve for now. most likely nothing internal as far as performance mods.
just dont forget something like a safc to stop you from running rich on shifts with the BOV 
if you blow your headgasket, id almost go all out with ARP hardware, and MHG, and get it all cleaned up so that MHG can seal nicely. that way you do it once and there is little to no chance it will ever bother you again. i just dont trust the stock units too much.
if you blow your headgasket, id almost go all out with ARP hardware, and MHG, and get it all cleaned up so that MHG can seal nicely. that way you do it once and there is little to no chance it will ever bother you again. i just dont trust the stock units too much.
I always knew about fuel cut...and just 2 weeks ago I experienced when my buddy took me for a ride in his AWD DSM Turbo...OUCH. It is like hitting an invisible wall. Go AFM/MAFT and you'll be good.....for now.
....for now.