Injector sizes

[tucky]

I'm looking at an engine re-build in the next year or so. Forge pistons, uprated con-rods, metal head gasket, hydra ecu, head job and running the car @6 psi. What size injectors should I go for?

[jhenty]

you can run 6psi on stock internals with the right fuel setup, why are you only planning on running 6? Some members here have used up to 8psi with stock injectors and the right fuel setup. The next step up would be 315cc and if your going real big I suppose 450cc. But for 6psi your stock injectors are fine, but upgrade to a return style fuel system and run a fuel pressure regulator. Jim's fuel mod is also something you should pick up.

[Akfahad]

^^^agreed...many respectable guys on here, with their applications to back it up, you don't need to upgrade your injectors for just 6lbs., unless you want a little security or something.

[tucky]

The prob is the trd supercharger is a m45 and I 'm worried about the heat it will produce over 6psi.

[crispone]

The prob is the trd supercharger is a m45 and I 'm worried about the heat it will produce over psi.

????



-crisp

[woa_its_j3ff]

The prob is the trd supercharger is a m45 and I 'm worried about the heat it will produce over psi.

????



-crisp

its okay Crisp, not everyone is very into detail like you

[Akfahad]

The prob is the trd supercharger is a m45 and I 'm worried about the heat it will produce over 6psi.

well...if your worried about it then upgrade them. I have bigger injectors, thought I needed them anyway and found out later it wasn't completely necessary. Just know that your gonna have to dyno tune once you do all your fuel mods, you'll be running extremely rich.

[Eye8Pussies]

although the blower does create a bit of heat, the heat is by no means excessive actually....

the air it outputs would be quite definately warmer than stock, but the s/c itself runs cooler than the stock intake plenum

if you're really worried about preignition, I'd get a fuel cooler instead

[crispone]

The prob is the trd supercharger is a m45 and I 'm worried about the heat it will produce over psi.

????



-crisp

its okay Crisp, not everyone is very into detail like you

...well... my confusion is over what symptom or failure mode the injector deficiency is being speculated. If I am understanding the english correctly, then the concern is more toward the matter of NET HEAT independent of the matter of psi... In other words, the concern was expressed, and then comments pertaining to safely running at 6 and 8 psi were given with stock injectors. My question would be with regard to where the HEAT is feared/noted to be coming from. DOES YOUR CAR RUN HOT? Perhaps there is an issue with AIR/FUEL ratio, but at the boost levels you are running, it should NOT be related to the SIZE of your injector... in OTHER words, there is some OTHER FAILURE MODE... (or else you are just paranoid?)

I would suggest checking your AIR/FUEL ratio... if not by a metering device, then by the tell-tale signs provided by plug reading and piston head observation through a plug hole, etc... and there are others.

Is there a LUBRICATION issue?

etc, etc, etc...

Why the jump to injector size concerns? There are formulas for determining this, but it would take some time to transfer all the calculations! (I've got them in a book here somewhere...)

Just for reference, I run 440cc injectors in a very efficiently tuned 3.0 7MGTE running 16lb boost at about 390HP.... but that is RIGHT AT the limit of the injectors duty cycle.....

Remember, LEAN is POWER and RESPONSE.... (yes, I know... TOO LEAN is motor damage.... injector size doesn't sound like the issue at 6psi... but I could be wrong.)


EDIT ---> Ahhhhh.... I see now that you are doing a "complete" build-up... I would suspect you want "upward" mobility...? I'd definitely consider the proper injector for any EVENTUAL aspirations (pun intended) that you may have in the future... the key will be keeping the AIR/FUEL ratio in check and managing the gain curve effectively.... I suspect.

Good luck! (use formulas and your current and "potential" max setup for the variables... it should walk you right to that answer... BEATS forum OPINIONS anyday, for sure. In OTHER words, "engineer" your configuration, IMHO.)


-crisp

[CASTRO]

The prob is the trd supercharger is a m45 and I 'm worried about the heat it will produce over 6psi.

just to clarify for anyone, i believe that this comment was explaining the size of the supercharger unit. Just like a turbo, an m45 is the "size" of the TRD supercharger. Just for comparisons sake, those Pontiacs with the big V6's them use an m90 trim supercharger. Our m45 trim supercharger runs out of its efficiency when it is spun too fast and actually acts as a heater, so the added boost is offset by more problems due to the heated air. I believe that the limits of efficiency on the m45 trim are around 9psiand above.

I read all this information about the eaton style blowers over at the saturn ION redline and chevy cobalt SS forums. Turns out that those domestic 4cyls use an m45 trim as well!

Long story short, you spin the s/c up too fast, and it no longer is able to correctly compress air efficiently and actually heats the air so much, the added boost is worthless.

Crisp, how'd I do on adding detail? lol j/k Trying my best to be as detailed as possible. Its rare for me to type this much as I'm a lazy guy. haha

[tucky]

Thanks for that , I 'm sorry if I did not make myself clear. I always thought the trd unit used a eaton m62. When I found out it was a m45 I was concerned about the amout of heat generated when the boost was increased, thats why I was looking @ running 6psi. So when I have my engine build done I'm not putting the engine in danger. What I'm looking at is forged pistons, uprated con-rods, port and polish and running 6 maybe 7 psi. I have already have a set of custom headers, custom exhaust with no cat, water injection.

I'm just doing the groundwork for an engine build to be capable of running 6-7 psi and would like peoples thoughts on the fueling side of things.

[Akfahad]

If your gonna do all the work to rebuild the engine, might as well have the supercharger built and push more boost. Just my 2 cents anyways. Jim@ForeignAffairs has done quite a few supercharger rebuilds from what I remember.