H.p. loss at wheel how much?

Koenigturbo

Active Member
Oct 4, 2006
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Oxnard CA
Whats the approx h.p. loss thru the drive train or whats my aprox h.p. with these mods?
Here's my mods, 3' exhaust, 18 p.s.i., 57 trim, engine management, will use the Lexus if I need 550 injectors.
I'm trying to calculate what size injectors to use, R.c. has work sheet to use to select the correct injectors size. But they want to know what the horse power is at the crank. Every says, take it to a Dyno, How can I take it to a dyno, if I don't have injectors to even start the car, let alone go to Dyno. What? put my stock injectors in and see how it gose? I know every probably is gonna say 550 is the way to go. I've also heard 440 has also supported 425 h.p..Everybody's car is different, that why I can't get a consistant answer, yes this a dead horse. The work sheet should be posted as a sticky.
 

starscream5000

Senior VIP Member
Aug 23, 2006
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Drive train loss would be anywhere between 14-19% most likely, depending on your mods to the drivetrain, and if it's an auto or stick.

1cc per 1HP is a good rule of thumb, alon with no more than 80% injector duty cycle to be safe and make things last. In that case, 550cc injectors would be SAFE, for 440HP.
 

Koenigturbo

Active Member
Oct 4, 2006
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Oxnard CA
starscream5000 said:
Drive train loss would be anywhere between 14-19% most likely, depending on your mods to the drivetrain, and if it's an auto or stick.

1cc per 1HP is a good rule of thumb, alon with no more than 80% injector duty cycle to be safe and make things last. In that case, 550cc injectors would be SAFE, for 440HP.
Tanks!!! we can kill the pony now!
 

MassSupra89

Almost done.
Nov 3, 2005
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There are users who have done 500-550 with 550cc's
stock 440's have been proven to 400whp many times.
Always have your injectors flow tested and cleaned if you're unsure of their condition though.
 

Keros

Canadian Bacon
Mar 16, 2007
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Calgary
MassSupra89 said:
There are users who have done 500-550 with 550cc's
stock 440's have been proven to 400whp many times.
Always have your injectors flow tested and cleaned if you're unsure of their condition though.

I've seen this too.

Would I be correct to say that it is a safer route to get the 550's with the Lex AFM in order to gurantee that increased air flow matches the increased demand for fuel?

Also, with the LexAFM/550 mod, is an AFPR necessary or recommended? Or more specifically, are any fuel delivery mods required to get the most out of the 550cc injectors?
 

MassSupra89

Almost done.
Nov 3, 2005
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Keros said:
I've seen this too.

Would I be correct to say that it is a safer route to get the 550's with the Lex AFM in order to gurantee that increased air flow matches the increased demand for fuel?

Also, with the LexAFM/550 mod, is an AFPR necessary or recommended? Or more specifically, are any fuel delivery mods required to get the most out of the 550cc injectors?


Yes that's correct. The 550's being 25% larger than the stock injectors are perfect for the LexAFM which is roughly 25% larger than our stock AFM. You've got the right idea.

And as Starscream said, a Walbro 255lph pump and an AFPR will give you the most tunability and performance out of the 550's and AFM. Also an SAFC and Wideband will be your best tool for tuning with these.