Injector size?
Thread Starter
Safety Car
Joined: May 2003
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From: Houston Texas
Injector size?
About to install a 6 psi vortech. Hooker shorties and corsa exhaust, MSD wires, coil, MSD BTM, 104's and installing mild cam with rockers at same time. Until I blow my engine(it has a few miles on it) and build it for a blower what size injectors 24 or 30#. Also if I go to a FMU which one do I need. Also do I need the 255 lph racetronix intank pump or external one. Thanks for your input. :)
Race Director
Joined: Feb 2002
Posts: 11,268
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From: Honolulu, HI
Re: Injector size? (BAM92)
I think 24lb injectors with a Vortech FMU should be fine. I would upgrade my pump if I were you. Get an AFPR with the Walbro GSS340 255lph fuel pump. You might want to call Vortech to find out what your FMU ratio should be set at for you application.
And of course, you'll need to tune it properly to get the max HP out no matter what you bolt to it. THat's the point I'm at now. Without datalogging, Wide band info, I can't get the most that my motor has to offer.
:cheers:
And of course, you'll need to tune it properly to get the max HP out no matter what you bolt to it. THat's the point I'm at now. Without datalogging, Wide band info, I can't get the most that my motor has to offer.
:cheers:
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From: A dealer near you.
Re: Injector size? (BAM92)
Stay away from using FMU's. Get a proper HQ 1:1 FPR and properly sized injectors. You can always go oversize on the injectors as it is better to have a bit too much then not enough. Remember injectors work best at or under 80% DC and under normal FP's. Using an FMU to compensate for undersized injectors by running super-high FP causes complications with your pump, injectors and ECM calibration.
Injector size can be calculated by factoring in your FWHP, BSFC and max. engine RPM. Always select an injector that will provide the fuel you need at a maximum DC of 80%. A little room for margin (i.e. +10-20%) is a good idea.
[Modified by Racetronix, 4:41 AM 7/29/2003]
Injector size can be calculated by factoring in your FWHP, BSFC and max. engine RPM. Always select an injector that will provide the fuel you need at a maximum DC of 80%. A little room for margin (i.e. +10-20%) is a good idea.
[Modified by Racetronix, 4:41 AM 7/29/2003]
Drifting
Joined: Jul 2001
Posts: 1,897
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From: La Fontaine Indiana
Re: Injector size? (Racetronix)
Stay away from using FMU's. Get a proper HQ 1:1 FPR and properly sized injectors. You can always go oversize on the injectors as it is better to have a bit too much then not enough. Remember injectors work best at or under 80% DC and under normal FP's. Using an FMU to compensate for undersized injectors by running super-high FP causes complications with your pump, injectors and ECM calibration.
Injector size can be calculated by factoring in your FWHP, BSFC and max. engine RPM. Always select an injector that will provide the fuel you need at a maximum DC of 80%. A little room for margin (i.e. +10-20%) is a good idea.
[Modified by Racetronix, 4:41 AM 7/29/2003]
Injector size can be calculated by factoring in your FWHP, BSFC and max. engine RPM. Always select an injector that will provide the fuel you need at a maximum DC of 80%. A little room for margin (i.e. +10-20%) is a good idea.
[Modified by Racetronix, 4:41 AM 7/29/2003]
If it is idle quality you are worried abouy you have to go a lot bigger than that before it becomes a problem. Like matt points out tuning is critical best way to use a DFI :cheers:
Drifting
Joined: Feb 2002
Posts: 1,952
Likes: 2
From: Little Rock Arkansas
Re: Injector size? (black bart)
:iagree: If anyone has been on here very long you've probably read my vitriolic diatribes on the use of FMU's...They're a bullsh|t stopgap measure the s/c mfg's came up with so people could "easily" adapt s/c's to stock engines without (supposedly) needing to do any reprogramming...THIS IS NOT THE WAY TO PROPERLY DO THIS!! Size the injectors properly and use the ECM to correct; spiking fuel pressure like FMU's do is NOT SAFE nor conducive to ideal power.
-Jeb
-Jeb
Thread Starter
Safety Car
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From: Houston Texas
Re: Injector size? (jburnett)
I bought FMS 30# injectors already. So you are saying I should go bigger. I already am planning to buy racetronix's pump next week. My kit came with water injection. Any thoughts. Kinda didn't want to go that route so I am asking for advice from you guys. Have not bought FMU though and now I am definely not. At this point I have the exhaust and ignition on car already and have blower almost ready to go on just want to get fuel thing right or almost right on first try. As I stated before since I have to take everthing almost off front of motor I am going to do mild cam and rockers same time. 36# or 42# injectors are OK?
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Thread Starter
Safety Car
Joined: May 2003
Posts: 4,283
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From: Houston Texas
Re: Injector size? (Racetronix)
They say the kit gets you to 425 fwhp. I am going to add mild cam and rockers so conservatively no more than 440hp. Rpm if I had to guess 5500. Hope that helps.
Drifting
Joined: Jul 2001
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From: La Fontaine Indiana
Re: Injector size? (BAM92)
I would use 42lb. injectors like I said in earlier post no drawback if they only reach 70% duty cycle that just leaves room for future mods. Go to http://www.smokemup.com click on auto math it shows 500 flywheel hp requires 43lb injectors your 30lb at 60 lb fuel pressure will flow like 35lb injectors. I have a lot of almost new injectors because of this. I listened to tpis and others and wasted a lot of $$$$$$$$$$$$$$$$$$$ Anyone needing injecters I have all sizes you could say I have been their done that.
Thread Starter
Safety Car
Joined: May 2003
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From: Houston Texas
Re: Injector size? (vvv90)
This is why I am learning from your mistakes as my budget does not permit too much trial and error. I am going to sell my 30#s and go for the 42's. Thanks everyone for you 2 cents as it is worth alot more too me. :thumbs:
Melting Slicks
Joined: Mar 1999
Posts: 2,535
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From: Rochester NY
Re: Injector size? (vvv90)
for fairly low boosted motor, I would run 42#. For High boost application I would 50# or 75# with modified ecm. I am running 50# but will need to run 75# down the road
Bruce
Bruce
Drifting
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From: La Fontaine Indiana
Re: Injector size? (BAM92)
If you go to Jeg's web site and look at their holley injectors it will show that the 42lb are good for 750hp. but they won't do it. My experience has been that the auto-math at smokeumup is a lot closer to being right. The windings in the coils are not designed to open against high pressure at high rpm they will overheat and fail. When you go to the big injectors you will have to reprogram the ecm. Later when you go with the forged pistons and more boost all you will need to do is reprogram the ecm for the new power instead of buying new injectors everytime you change something. Best way to do that is with a DFI what I have saved you on buying three sets of injectors before you get to where you need to be you can use that money to buy a dfi :lol: I had a set of 55# injectors sold them now only have 19-24-42 left all are nearly new lot of $$$$$$$$$$$ down the tube.
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Re: Injector size? (BAM92)
We recommend the Delphi 42's listed on our web page here: http://www.racetronix.com/Racetronix..._Sale-42s.html
If you would like larger low impedance injectors here are:
Flow-matched 50's: http://www.racetronix.com/Racetronix..._Sale-50s.html
Flow-matched 57's: http://www.racetronix.com/Racetronix..._Sale-55h.html
If you would like larger low impedance injectors here are:
Flow-matched 50's: http://www.racetronix.com/Racetronix..._Sale-50s.html
Flow-matched 57's: http://www.racetronix.com/Racetronix..._Sale-55h.html
Drifting
Joined: Feb 2002
Posts: 1,937
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From: Arvada CO
Re: Injector size? (Racetronix)
i heard disc injectors are junk and you want to stick with pintle? i think i spelled it right? i could be wrong or right?
Please clarify...
Disc internal?
or
Pintle internal?
which is better! :D
Please clarify...
Disc internal?
or
Pintle internal?
which is better! :D
Supporting Vendor
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Posts: 1,573
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From: A dealer near you.
Re: Injector size? (krivera)
You have it the wrong way around. The disc injectors are excellent quality and work quite well. They have stainless steel internal parts, have a quicker reaction time than pintle injectors and are quieter. Pintle injectors are going the way of the dinosaur. Most new injectors are either disc or ball/seat.
We recommend you read our ad here for the advantages a disc injector has to offer over pintle injectors: http://www.racetronix.com/Racetronix..._Sale-42s.html
[Modified by Racetronix, 4:35 AM 7/31/2003]
We recommend you read our ad here for the advantages a disc injector has to offer over pintle injectors: http://www.racetronix.com/Racetronix..._Sale-42s.html
[Modified by Racetronix, 4:35 AM 7/31/2003]
Drifting
Joined: Feb 2002
Posts: 1,952
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From: Little Rock Arkansas
Re: Injector size? (Racetronix)
:iagree: Racetronix is ON!! Pintle type injectors are the OLDEST type of injector and the most unreliable (particularly when subjected to greatly increased pressures). Think about a mechanical pintle type injector?? Can't think of one off the top of your head? Think Quadra-Jet and their replicas; they use needle and seat just like a pintle injector and are VERY pressure sensitive when compared to a Holley...
-Jeb
-Jeb
Intermediate
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From: Stockholm
Re: Injector size? (black bart)
Later when you go with the forged pistons and more boost all you will need to do is reprogram the ecm for the new power instead of buying new injectors everytime you change something. Best way to do that is with a DFI.
Also, any special injector-brand you recommend for a supercharged L98? I'm probably going procharger this winter
[Modified by faj, 8:40 PM 8/11/2003]
