smg944

iTrader: (34)

ok brought my car to the local dyno to tune it out a bit more, and bring up the boost some. so i did, tuned it out to 13.5 psi and made 334whp with air intake temps in the mid 40's. seemed pretty good, was driving nice and strong. on my way home i decided to see my fuel inj. duty. well it was pushing 90% by redline with that tune. with 550/1200cc injectors and a supra pump, 11.5:1 afr doesnt add up to the amount of fuel going in. i am a bit stumped at what could be causeing my high fuel %. any input appreciated... dyno attached.

ErnieT

iTrader: (2)

Your ok. Main thing is to watch your fuel pressure and a/f ratios. If they are stable, no worries. If your still concerned. Upgrade your secondaries to the 1600's. Stock primaries are good to about 450rwhp.

smg944

iTrader: (34)

i just dont understand where all the fuel is going. 334 whp at 11.5:1 afr, with 90% injector duty... thats all i can get out of it. if i bring the boost up ill be to close to 100% injector. i am going to check into the fuel pressure, maybe a vac line is off.... i hope. thanks for the reply.

ErnieT

iTrader: (2)

Whats your base fuel pressure? It should be at around 38-40 static.
Also your running rich which also dumps alot of fuel, using more injector.

Wargasm

That adds up perfectly based on my rough formula for rwhp....

max rwhp = (total injector capacity in cc/min) / 10

so you get 550 + 550 + 1200 + 1200 = 3500

3500 / 10 = 350 rwhp

So you're at 334 and at 90%... makes sense to me!

Bumping up the fuel pressure might help some, but really you should consider going to 1600 seconaries IMO.

smg944

iTrader: (34)

from most of the posts i have seen, i could have sworn that you could make 400whp on 550/1200cc injectors. i could be wrong... also i checked rx7.com with there fuel calculator and i came up with. 475.5 hp with 90 % inj. duty. im sure that is flywheel hp , also not sure how accurate there calculator is...

ErnieT

iTrader: (2)

Its a really easy solution. If you worried about it, then just buy the 1600 injectors and end your worries and possible problems.

smg944

iTrader: (34)

i was planning on buying the 1600s sooner or later. once i port the motor and up the boost some more i think i would need to. i just figured there was something else that was holding fuel back, since i had seen some 550/1200 setups doing close to 400whp with enough fuel for it. ill give the fuel pressure a check , just to see... thanks for the responces.

smg944

iTrader: (34)

also check out this apex rx6 owner. he made 379 whp with 4x850's , thats 100cc less then my setup and 45 more whp on pump gas...

https://www.rx7club.com/showthread.p...x6+turbo+specs