Horsepower vs Injector Size

1132 Views 17 Replies 8 Participants Last post by Chicago_DSM, Nov 26, 2005

92fwdMITSU

Discussion Starter · Nov 23, 2005

I'm new to the DSM world and I searched but couldn't find quite was I was looking for. I'm building up my car this winter with hopes of a low 13sec slip my first time out in the spring and then a 12sec slip by the end of next summer.

So far I have:
Dejon hard pipes
K&N Filter
Evo3 B16g
Ported 2g exhaust manifold
VRS 2.5" turbo back w/ O2 Elim
190lph fuel pump
Datalogger
SAFC-2
JoeP boost Control
Autometer Boost & EGT guages
FP2 camshafts

I am now looking to get injectors for my car and I'm debating between the 550cc or 580cc or 650cc. The 580's and Precision injectors and are more expensive than the others which are Lucas injectors from FIC. I would rather go with the 550's and have more accurate fuel control and not have to worry about leaning them too much with the SAFC and getting too much timing. But my question is if the 550's will be adequate to get me the 320-350hp I'm looking for and a 12sec slip??

I don't plan on taking this car any further than that since it's my first build so lets not worry about upgrading in the future. Can 550's flow enough fuel to support 20ish psi of boost and 320+ horsepower? I know going to 650's is on the safe side and will allow future expansion but I'm not planning on upgrading and I don't want to have timing issues like previously stated. So will 550's do the job?

Thanks,
Justin B.

1 - 18 of 18 Posts

greenstreak

· #2 · Nov 23, 2005

550s should get you to that goal safely.

Another option if you want to run something larger is either a keydiver chip to give you a base compensation for the larger injectors. That way you are not hiding as much airflow as you would without it or an adjustable fuel pressure regulator.

You can lean the entire fuel curve out (or richen it) with fuel pressure adjustments and then fine tune with the Safc.

92fwdMITSU

Discussion Starter · #3 · Nov 23, 2005

Yeah, I was thinking about going the AFPR route and then using the SAFC for fine tuning. BUT, I went with the 190 pump in the first place because I didn't want the 255 and a AFPR because of the extra cost associated with it and I didn't think I'd need that big of a pump for my goals.

Can you provide me with a little more info on the keydiver chip? Is that just to compensate for bigger injectors or can I also raise the rev limit and do other DSMLink-esque stuff with it?

I think it the spirit of being a cheap newbie DSMer that I'll go the 550's route because I don't want to find myself throwing even more money into this car than I have to. I think tuning will be the biggest hurdle for me to get into the 12's, especially with FWD and the traction issues.

greenstreak

· #4 · Nov 23, 2005

An adjustable fuel pressure regulator is not only for the regulator overrun problem with a large pump. It is for tuning a small pump as well.

Read and you will find all the answers to your questions.

http://www.dsmchips.com/

noreaga0221

· #5 · Nov 23, 2005

Tires and lsd would be the most important issue to getting into the 12's.

92fwdMITSU

Discussion Starter · #6 · Nov 23, 2005

Thats kind of why I was figuring 13's the first time out. I'm putting the car on a healthy diet and i allready have the motor mounts and KYB AGX's with Eibach Prokit springs to help traction.

My first run in the spring will most likely be on teh stock steel 16 inchers with balding tires. I'm sure traction will be an issue but if I can figure out how to drive it that way I'll be better off for when i get good tires. New rims and tires are definitely going to happen next spring. I've allready been looking and I think I've decided on Axis Reverb's in black.

I'm not sure if I want to go with an LSD or if I just should get a pair of slicks to put on the steel wheels for track duty. Actually, I really want an LSD but the 850+ price tag kind of sucks. I'll probably just deal with the open diff until I get more knowledgeable about DSM's and then I'll find an AWD shell I can swap the motor into once it's built.

But anyway, 550's should do the trick?? I plan on ordering these the day after Thanksgiving so I'd appreciate some more knowledgeable peoples input

Thanks

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noreaga0221

· #7 · Nov 23, 2005

LSD !=850+

bmtrans/turbotrix lsd = $200. I got one and love it.

Drag racing on bald tires = waste of admission fee

You have all those things but can't afford some better tires before spring?

Slicks won't be nearly as useful when you are only spinning 1 tire.

And how about some type of intercooler? A supra smic will be perfect for your setup.

Also about the 'more knowledgeable peoples input', first you have greenstreak who has 2348732 posts, site admin and not to mention works for the man who probably kept the dsm community alive by selling discounted oem parts and me, who has already been down the road you are about to partake on. How's [email protected] in a fwd on street tires. I know what helped me and what didnt. If you aren't going to listen and just do what you already wanted to do then don't ask for help.

Ps. I went that fast on 450's.

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92awdlazer

· #8 · Nov 23, 2005

noreaga0221 said:
LSD !=850+

bmtrans/turbotrix lsd = $200. I got one and love it.

Drag racing on bald tires = waste of admission fee

You have all those things but can't afford some better tires before spring?

Slicks won't be nearly as useful when you are only spinning 1 tire.

And how about some type of intercooler? A supra smic will be perfect for your setup.

Also about the 'more knowledgeable peoples input', first you have greenstreak who has 2348732 posts, site admin and not to mention works for the man who probably kept the dsm community alive by selling discounted oem parts and me, who has already been down the road you are about to partake on. How's [email protected] in a fwd on street tires. I know what helped me and what didnt. If you aren't going to listen and just do what you already wanted to do then don't ask for help.

Ps. I went that fast on 450's.

ewwww 92fwdmitsu got set straight on that one.....

rad_dsm

· #9 · Nov 23, 2005

bmtrans/turbotrix lsd = $200. I got one and love it.

Do you have any info on this or a link. I searched and didn't find any info.
thanks

noreaga0221

· #10 · Nov 23, 2005

rad_dsm said:
bmtrans/turbotrix lsd = $200. I got one and love it.

Do you have any info on this or a link. I searched and didn't find any info.
thanks

You serious? http://www.dsmtalk.com/forums/search.php?searchid=203000 I just copied and pastes bmtrans into the search button and hit enter. Plenty of info in them listed threads. Then try searching for titles on 'lsd' in a title only search will bring up alot of info.

92fwdMITSU

Discussion Starter · #11 · Nov 24, 2005

More knowledgeable as in "more people IN ADDITION to Greenstreak and yourself". I can see how you would misinterpret what i said but I didn't say it in that regard. Sorry for the confusion. I am well aware the greenstreak is very knowledgeable and i appreciate his advice and your own. I was just hoping even more people with experience would come in too.

On the intercooler.... I was looking for a supra sidemount or possibly a small frontmount, haven't quite decided yet.

On tires.... I have money for a decent set of tires right now but since the car probably won't get out of the garage until spring I don't see why I would buy tires right now. I'll get the motor and suspension setup first.

How did you go that fast on 450's?? I curious and eager to learn, I wasn't trying to dissrespect you at all and I'm sorry you took it that way :/

noreaga0221

· #12 · Nov 24, 2005 (Edited)

14b + 55 shot nitrous + race gas + supra smic.

You gotta get the motor set up first? Is the first post just a wish list or do you actually have all those things? Or do you have to build another motor?

greenstreak

· #13 · Nov 24, 2005

The supra sidemount is actually a great intercooler and very stealth for your objective. If money is tight and you want to put it into other things like suspension this is a good place for now to save money over a fmic setup.

You can get away with a smaller injector on racegas than you could on pump gas. Still, with fuel pressure adjustments you can really extend the useful limit of a smaller injector.

canada4g63

· #14 · Nov 24, 2005

Slicks will help alot.

92fwdMITSU

Discussion Starter · #15 · Nov 25, 2005

I have all the stuff listed in the first post. It is piled up in my room awaiting install. I say get the motor set up first because I won't be driving the car until spring so tires won't allow me to do anything at this point in time.

I'll keep my eyes out for a Supra sidemount either on here or Ebay that I can use for the setup. I like teh stealth aspect of it and the simpler piping involved.

I'm sure I'll run race gas at some point at the strip just to see what it can do, but I'd like to reach 12's on the 93 octane pump gas.

I think this thread kind of got off track because I intially was just trying to figure out if injector size correlated to horsepower at all. Like 450's are good for 280hp, 550's will get you to 400hp, 650's will net 475hp...... and so on. I realize that it's all in the tuning but I was wondering if there's a blanket statement that would work.

Thanks for all the input, I appreciate it.

greenstreak

· #16 · Nov 25, 2005

There really isn't a blanket statement like what you are looking for. Too many variables to pin it down that easily.

diambo4life

· #17 · Nov 25, 2005

Tires (DRs or Slicks) are a must if you want to see anyhthing in the mid-12's or quicker.

Chicago_DSM

· #18 · Nov 26, 2005

btw: what was failed to mention was those keydiver chips are great for compensating large injectors, but first you need an EPROM ecu...Instead of spending $350 on an EPROM & a chip, you could buy either an AFPR, new tires, wideband 02, an LSD or +++ who knows...So, I would eliminate that variable...Good tuning, good driving, race gas + big boost, good tires, supporting mods and BOOM! 12's no problem on a fwd..

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