I'm putting 24lb injectors in my iroc to support my dry nos kit, but was wondering if i needed a new prom. I'm running one of those hypercrap chips with an msd adjustable timing thingy. Will my current prom adjust for the change in fuel output?

 

1 - Don't spray a dry shot on TPI.
2 - You don't need a new prom. But tuning it will help.
3 - TAKE OUT THAT CHIP.

Most of the aftermarket chips use more "agressive" timing. If your too advance when spraying. . . . . . BOOM!

 

no crap, that's why I'm using that MSD adjustable timing regulater. Just need to know about the 24lb injectors. Do I need a custom prom with 24lb injectors????

I'm not some fast and furious wannabe

my dry kit work great with my TPI so I'm not sure what you mean by that first "rule of thumb"

 

technically, yes you should have a custom chip to run 24lb injectors, considering 22lb injectors are stock....but it is possible to get the tuning fairly close by experimenting with your fuel pressure and watching your O2 sensor values, or just getting an air fuel gauge.

 

Stock injectors on an l98 are 19lbs

 

the block learn multiplier and integrator portions of the ECM have enough adjustment to self learn the new fuel values from the O2 sensor for a 22 to 24 switch. as a matter of fact I helped a guy put a votech A-trim (back when that was all there was) on a 89 iroc 350 and we put motorsport 30# injectors and it still learned them but it was getting close to its max internal self adjustment according to the scan software we had at the time. I like the 51xx series dry systems from NOS on TPI cars, but only to around 100 hp then I switch to wet flow (not particularly ideal on the tpi intake). these systems crank up the fuel pressures on the injectors and the junky ones GM used on the TPI cars (like the rochesters) can lock closed at these pressures and a dangerous lean condition can result. the ford injectors have a higher pressure lock threshold. that why I like to install 19# stang injectors on the 305 cars with the same setup or with blowers.

 

Stock injecters on a 350 TPI are 22 lbs
Stock injecters on a 305 TPI are 19 lbs

 

heres the 2 pennies that i will offer-(whether you like it or not) hahahahaha-i will try to go easy too-question #1) is your life requiring more worries, concerns and complications? #2)are you seeking ways to complicate the life you are enjoying? #3) are the parts in your plan stuff thats already laying around the garage? #4)are you fully pissed at me yet? otay i would be too. you are making this too complicated-ford 24 pounders are actually closer to 26 when rated at tpi fuel pressures. if there is no super ram on the engine serving the induction duties-the wet 150hp kit is the only way to go. dunno if you recall, but when is n2o meant to be injected into the motor? correct-loud pedal is flat down. very good so far. in that situation what mode does the ecm switch to? correct-open loop. now knowing fully that several companies have pretty much "scienced out" the lower hp level tpi kits. those kits im speaking of happen to be the wet variety. and being your car is already equipped with a timing retard more accurate and flexible than any add on box why are you going to open up such a huge dialing in curve in your attempt to get only 100 hp. here we go-way back way in 1987 or 88 i put a nos tpi kit on my 305 that i bought off a guy from the valley who wrecked his vette using it. 2 levels 100 hp jets for 305 and 150 hp jets for 350. way back then a new company was offering these chip thingies for cars-wow-i said to myself-and got one too. you got it- big ol stage 2 power chip im looking at it now cuz i took it out for the blower and reciept says 4/88 purchase. i mercilessly pummelled the 305 till the trans said seeya and the real art carr redid it. later swapped in the 406 and 150 jets and behaved in the same irresponsible way only faster. never had one lick of a fry run fu-kup but did blow the throttle body butterrflys backwards blew up the dual snorkle air cleaner plastic duct and maf ONCE as i was learning about cam overlap and slow idle speeds the lesson was -hey idiot dont inject n2o below wot-so i did it at idle and kerbam what a f--king shrapnel laced death blast it was i wish i had me on camera back then-be funny now-anyhow my advise is run a wet kit leave the hypertech in there and enjoy. percent wise the stuff isnt flowing enough to warrant all that work-save that for a blower-i have the n2o kit still if you want it -im tellin ya its way to easy to do it why put youself thru all that. seeya i also can share the secret of 15 pounds in a 10 pound bottle if you still like me after this.

 

This first one is a misconception because almost all bosch injectors are rated at a specific standard "BAR" (pressure), I used to believe this same thing until an injector manufacturer set me straight. "that is why..." he says, "we can sell you the same 19#'s for your stock 5.0 camaro or mustang not just because they are close in flow. as far as putting 15 #'s into a 10# bottle, if you think low rpm nitrous engagement is bad you shoud see a car that has had the safety burst disc pop on the bottle and knock out all the glass because of that very thing. nice ride! otherwise right on GGape!

 

seen a buddy have a mishap right along those unfortunate lines-dont be parking in a socal summer parking lot whilst full. im not sure what you are meaning about the injector sizes. bosch has never disclosed to the general public an exact flow rating for each part #. application is soley according to a specific use. thats what i have understood from my vendors-bosch is supplied (mainly) to me thru a distributor in the san fer. valley. and ive sniveled and whined and tried every workaround i could, but they aint lettin go with any specific tech. reference other than the generic"no smoking while working around gasoline" sort of nonsense. what i meant is that the svo rating, or motosport or whatever ford way of rating those injectors (not bosch) is at a lower pressure rating than what we typically use in our tpi setups, and if we flow rate those same injectors at the higher pressure we arrive at a bigger number. im running a set of the old style ford injectors commonly called 24 pounders-blue top and they are the pintle style 1 hole as compared to the 4 hole lower performance svo style out now. they have the bosch part # on one side and the ford # on the other-heres what they were removed from-1989 ford super duty flatbed tow truck. 460 ci-when i slapped in a new motor-in went the new injectors. kept the oldies cleaned them and aok. so we dont really know what the injector(s) in question are rated at officially-by bosch-cuz they aint tellin-whats out on the net as far as flow rates go could be from some pirated bosch info-but most likely is the commonly accepted, independently arrived at flow #'s. if somebody has the missing info -fess up and tell. are any vendors selling bosch single pintle style injectors in a 30 lb rating?-red top tried to get them thru motocraft by application-89ish super coupe 3.8 sc motor and got the 4 holers-same thru the other vendors-ACCEL is touting "bosch style" whats that mean?

 

fyi-definetely for sure in 85 and MAYBE 86 gm used the good bosch pintle style injector. i have them in my garage from the orig 305. i agree with the rochester statement-poopoo injectors-but the 19 pound ford stang injectors are now the 4 holer kind(disc type?) methinks. i really want some old pintle style 30's red from bosch, again, accel? :rockon:

 

The pintle style is better? I was under the impression that the 4 hole design was better. Guess Im wrong, but can anyone tell me why? It seems to me that the 4 microscopic holes would atomize fuel much better than the older pintle design. Tell me all ya know about em, cause I got a new set of Furd 19's on the way. I ran the Furd 24's in my GTA, they seemed to work great!

 

4 holers are ok unless the fuel pressure gets hairy. they actually have less mass internally to move around so the repeatibility of each pulse is better when the milliseconds drop down around 1.7, and i dont want to call all 4 hole injectors "disc type"cuz i believe that some lucas with 4 holes are of a different type. gotta try and stick with the "for sure". the pintle type that i was blowing my horn about are actually really heavy internally. pintle weighs in up there-but they really shine when boost #'s go up as well as the pressures in the fuel rail-100 psi and they still kick. if anyone knows the construction of the 4 hole injectors in question, chime in

 

Ok got ya. My problem is the car is idling like crap, and just feels worse and worse to me day by day. They are the "grey" (rochester maybe?) factory injectors. I have heard bad things about them, but not sure. Shes only got 44k origonal on it, BUT... before I put on my afpr, it idled perfect. So I slapped on the AFPR, bumped it up to 48, and idle went to hell. Put it back down to normal, still to hell. So I did a pressure check, and did lose some PSI after the car sat a while, but not all that much to cry about. I just traded my friend my used 24's for a new set of 19's. Cant beat that. The thing that pissed me off is that I only ran a 14.51 at the track last night. Granted, its almost .5 better than before, I know theres somethin wrong. Also my clutch is about to bite it, so I guess I really cant complain.

Well, I guess well see what happens next week!

Oh yeah, if ya know why the factory 89-up grey injectors suck, lemme know, as Im just curious!

 

GRUMPYGREASEAPE, let's see some more pictures of that beast and some 1/4 mile et's and mph #s!

I can't wait to get my 406 together.

Thanks!

 

"bosch style" does not refer to any internal configuration (pintle, disc, etc.), but instead refers to an external configuration, the upper and lower o-ring fitment (fuelrail to manifold) the aproximate length, and electical plug configuration that we chevy and them ford guys usually use along with many other cars import and domestic. BAR is a pressure measurement (I think its metric but I cant say for sure) you see it on your nice fuel pressure test gauge sets, in the manuals for repair usually in parethesis next to a PSI rating. both chevy and ford injectors are flowed and the same BAR (pressure) for determining thier rated flow along with a short list of other car makers. we extensively use ford (formerly "SVO", formerly "ford motorsport" now "ford racing") injectors here in chevys and fords especially the 24#,30#,42# because they have features of many race injectors, like a high pressure lock thresh hold, good spray pattern, good anti-clog, close flow levels, high impedance, and the price is half that of other injectors with less features. when a larger than 42# injector is needed or a different impedance then there is no other choice than to get a different kind, we usually use flow matched and serialized Delphi's we sell them for about $500 to $575 Depending but the fords we sell for about $180 to $325 depending.