'88 5-speed dyno log
03-13-2013, 03:06 PM
#46
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Side note - I can't believe 19# injectors were spec'ed all the way up to GTS.
Could only have been for low rpm emissions.
Even the 24# are hitting 90% duty past 5000 rpm at 12.5 AFR, with half injector rate disabled.
I thought about going to 30#, but I'm going to see if the LH2.3 half rate can be tuned properly.
(Half rate starts at ~5100, stock. I'll probably push that a little higher.)
With the S3, half rate isn't needed with their stock 24# and a S4 FPR. (S3s just can't breathe enough over 5200 rpm.)
Plus, I dumped the half rate code for space for my own.
Could only have been for low rpm emissions.
Even the 24# are hitting 90% duty past 5000 rpm at 12.5 AFR, with half injector rate disabled.
I thought about going to 30#, but I'm going to see if the LH2.3 half rate can be tuned properly.
(Half rate starts at ~5100, stock. I'll probably push that a little higher.)
With the S3, half rate isn't needed with their stock 24# and a S4 FPR. (S3s just can't breathe enough over 5200 rpm.)
Plus, I dumped the half rate code for space for my own.
03-13-2013, 03:32 PM
#47
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If you are doing any kind of ST'ing, then 24# should be the first stop.
I might even go 30# with a GTS and a big exhaust.
24# will make full throttle fueling much more consistent, which allows even the stock EZ to perform well.
As you can see with my LH tune only, it made pretty good numbers with the stock '88 EZ.
The newer (multi-hole) disc type injectors may atomize better at low rpm, keeping low rpm emissions comparable to the 19's?
I might even go 30# with a GTS and a big exhaust.
24# will make full throttle fueling much more consistent, which allows even the stock EZ to perform well.
As you can see with my LH tune only, it made pretty good numbers with the stock '88 EZ.
The newer (multi-hole) disc type injectors may atomize better at low rpm, keeping low rpm emissions comparable to the 19's?
03-13-2013, 05:32 PM
#48
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If you are doing any kind of ST'ing, then 24# should be the first stop.
I might even go 30# with a GTS and a big exhaust.
24# will make full throttle fueling much more consistent, which allows even the stock EZ to perform well.
As you can see with my LH tune only, it made pretty good numbers with the stock '88 EZ.
The newer (multi-hole) disc type injectors may atomize better at low rpm, keeping low rpm emissions comparable to the 19's?
I might even go 30# with a GTS and a big exhaust.
24# will make full throttle fueling much more consistent, which allows even the stock EZ to perform well.
As you can see with my LH tune only, it made pretty good numbers with the stock '88 EZ.
The newer (multi-hole) disc type injectors may atomize better at low rpm, keeping low rpm emissions comparable to the 19's?
03-13-2013, 05:46 PM
#49
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You can use 19#...if you don't plan on making over 280 rwhp. 
19's will make it more difficult to tune at high rpm, and will likely produce inconsistent dyno results.
19's are already maxed out (>90% duty) with the stock chip, even with half injector rate over 5100 rpm.
(HIR = one big squirt per rev, vs. the normal smaller two squirts.)
24# are just adequate, with over 80% duty (ideal max) over 5000 rpm, at 12.5 AFR.
19's will make it more difficult to tune at high rpm, and will likely produce inconsistent dyno results.
19's are already maxed out (>90% duty) with the stock chip, even with half injector rate over 5100 rpm.
(HIR = one big squirt per rev, vs. the normal smaller two squirts.)
24# are just adequate, with over 80% duty (ideal max) over 5000 rpm, at 12.5 AFR.
03-13-2013, 08:03 PM
#50
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What fuel injector part number is it for the 24# ones, or will a 14.5 ohm impedence work in the S4?
Last edited by Mongo; 03-13-2013 at 08:59 PM.
03-13-2013, 09:56 PM
#51
Three Wheelin'
03-13-2013, 10:32 PM
#52
03-13-2013, 11:12 PM
#54
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03-13-2013, 11:27 PM
#55
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Regarding 24# injectors...
Anything rated for 24#, high impedance, should work fine, as long as they are clean (preferably flow rated).
This is old-school batch fire, not direct injection. Opening times, all that, whatever.
The injector is firing on the back of the intake valve. Once when it's closed and once when it's open.
Disc type (mult-hole) injectors will flow a bit more when they are run on full DC voltage, but flow the same as pintle type when pulsed, as they will always be when installed.
Anything rated for 24#, high impedance, should work fine, as long as they are clean (preferably flow rated).
This is old-school batch fire, not direct injection. Opening times, all that, whatever.
The injector is firing on the back of the intake valve. Once when it's closed and once when it's open.
Disc type (mult-hole) injectors will flow a bit more when they are run on full DC voltage, but flow the same as pintle type when pulsed, as they will always be when installed.
03-14-2013, 01:11 PM
#56
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Like these?
http://www.jegs.com/i/Ford-Racing/39...rentProductId=
Ford Racing#397-M-9593-LU24A
Fuel Injector
Flow Rate: 24 lbs/Hr @ 39.15 psi
Type: EV6 (Jetronic Connector)
Impedance: 11-18 ohms
8/pkg
http://www.jegs.com/i/Ford-Racing/39...rentProductId=
Ford Racing#397-M-9593-LU24A
Fuel Injector
Flow Rate: 24 lbs/Hr @ 39.15 psi
Type: EV6 (Jetronic Connector)
Impedance: 11-18 ohms
8/pkg
03-14-2013, 03:05 PM
#57
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Has anyone else seen 19 lb injectors at 90% duty cycle on a stock S-4 engine?
John Speake?
I've run 19 lb. injectors in a stroker, before, and made 330 RWHP. I did this with Shawn Smith's engine, during my R&D stage.
That's what is so confusing about what Ken is saying.
John Speake?
I've run 19 lb. injectors in a stroker, before, and made 330 RWHP. I did this with Shawn Smith's engine, during my R&D stage.
That's what is so confusing about what Ken is saying.
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714 879 9072
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Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
03-14-2013, 03:13 PM
#58
I think part of what Ken is talking about is headroom on the duty cycle. 95% duty cycle above 5000rpm is nearly static open, which does not leave room for error.
03-14-2013, 03:15 PM
#59
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Yea I don't think I'm gonna go the 'all out' route when it comes to making power. I'll be happy to squeeze another 20-30 out of the motor on a Shark Tune and still pass smog.
