Hey Guys, I started to swap out my stock 22lb injectors with some from a 95 Z28 that are 24lb units. I had talked to several people about this and they said it was an easy swap, no big deal. Even if you look on ebay, they advertise take out 24lb injectors as being a replacement for L98's and TPI motors. So I picked up a set off of ebay for around $150 and the guy claims they only have 32K miles on them, when I got them, they looked good. The point of my story is when I went to reinstall my fuel rail with the injectors attatched, they would not sit into the ports firmly. So I pulled it off and took one of my old injectors and come to find out, the stock 22lb unit is about 1/4 - 1/2 of an inch longer than the 24lb one. With my car being my only source of transportation I proceeded to grind down the support towers ont he intake that hold the fuel rail. I am not done with yet but it looks like it going to work. One thing that I may have to do is cut the bolts about 1/4" as well but I am hoping I dont have to. Has anyone else done a sway like this and this same problem??? I would love to hear from feedback if anyone has some.

Humm....the swap worked fine for me....I never compared the length of the injectors but I did not have any problems with the LT1 injectors being too short as not to seal up in the bores. I have been running them for 3 years now without any leaks.

Thanks for the input 406. Its weird, I have checked and checked and they just are not long enough. I have already ground down 3 of the 4 towers so I will finish grinding the 4th one tommorow and see how it goes.

Are you sure it even matters? The LT1 injectors are probably shorter because they are a different type of fuel injector. I know when I changed mine they were much shorter, but they fit perfectly.

I had the exact same problem with the summit 24 lb injectors and did the exact same thing to solve the problem...worked fine!

Thank you for the post poncho, I am feeling better now. I should have it all back together tommorow.

Poor college student must have a rich daddy for all those MODs

The overall length of the injector doesn't matter. Only the distance between o-rings. And i'd be really surprised if that was not the same given the many times i've seen people complete the swap with no issues, and including that aftermarket injectors are also truly universal (i.e. i know people that are running used aftermarkt.
87-88 TPI cars came with a different style injector than other TPI cars that has an extended tip. It looks longer than a regular injector, but i am sure they are still the same length. Before you fubar your intake grinding down the fuel rail towers, maybe you should measure again.

It's too late, he's already grinding........

Ed is right, the distance between the o-rings is the ONLY thing that matters. I can tell you it's the same.

The thing using LT1 stuff (I should know!) is that the clips for the LT1 injectors cannot be used in a TPI application. You will have to use the stock TPI clips or none at all.
TPI clips also go in the top grove, not the bottom groove like the LT1 injectors.

To clear up some things about my experience I am having with this. First, there was only one groove on the LT1 injectors to use and I used the TPI clips since the LT1 injectors did not have them.

Second, I think everyone is right, it probably should not matter but it just to be safe i want the injectors to go as far into the ports as possible.

Third, in response to 72LT1VETTE's comment, I take your comment personally. My life is not financed by my parents like so many other rich *** no working college students here in Austin. I work full time and I am full time college student. I have all of my own blood, sweat, tears, and more money than I care to count into my car. My parents told me and my brother when we wanted cars to go get a job and make sure you get your own insurance policy while we where at. Me and my brother have bought, sold, traded, worked on, and raced 31 cars between us in 6 years. Some of the highlights include 3 1969 Camaros, 2 IROC Camaro's, 3 1970 Chevelle's, a 1978 454 powered Z28, a 1966 Black 2dr Impala (Mafia staff car) and presently owned 1957 Chevy Bel-Air. None of our cars are show stoppers but they have all been daily drivers, we held the titles on all of them, and turned alot more heads than the kid driving mommy and daddys owned 4th gen F-body or Mustang.

This message board is not a place to bash one owner of a car just because he or she has done alot to it. It has taken me a long time to get to where I am today. My 1st car was a 1987 305 Camaro sport coupe with NO options that I gave $1,800 for. It was real POS but it ran, got me to work and school, and it was paid for. I told my self that one day I would have a really nice, really clean IROC-Z and a fully restored 1969 DZ302 Z28 or SS396. I have one half of my life time car goal completed. I support anyone working to own and drive the car of their dreams, that's why I do what I do, and that is why I am a member of this website.

Grow up TROLL!

Maybe Mr. 72LT1Vette is just jealous because he is broke and driving an OLD car with no REAL mods. Wasn't 72 the second year for strict EPA standards? Isn't that 72 LT1 like 220HP? I know a few STOCK L98 IROC's that would hand you your @ss and send u home CRYING to your DADDY cause you got beat. So before you come on here with all of your negativity why don't you check your own self? You've got some issues man.

THANK YOU ,IROC57!!!!!!! I have quit going to many F-body boards due to the 17-20 year old internet punk/know it alls.I still come here because that kind of child like attitude is not put up with.This is an info board,not a slam board!

I thought the LT1 injectors were LOW impedance and the TPI used HIGH?

I may be wrong just wanted to throw that out there!

i agree, there are a lot of those mommy daddy bought it for me punks around now days. im 19, i have 4 cars, 3 drivable, paid cash for all, worked on all of them, and worked my *** of since i was 15 to get my cars.

i know what your talking about, here in decatur, all the adm reps kids have nice cars with that gay punk attitude, most notibly the low down car gang, anyone from IL will know what i am talking about, almost all of them are punks and thugs.

they need to do reserch before they say stupid stuff.

back to the subject, i was also thinking about puting lt1 injectors on my 350tpi. my factory injectors fit loose in the cylinders, so i never thought that the smaller shaft on the lt1 would make a diff as long as the diamiter is the same.

i have a turbo i am going to put on my car and was wondering if anyone here knows if the LT1 injectors would be good enough to supply fuel for it? i know this is a power adder ? but i figured what the hell since i was already posting here.

thanks
anthony

FYI I am 53 years old, worked my way through college also and make over $100K annually. The 72 LT1 Corvette I have has matching numbers and is fully restored. Due to insurance reasons GM began using rear wheel horsepower (RWH) specs in 1972. The LT1 was set at 270 HP with 360 Foot pounds of torque. That's 330 HP measured the old way, the same as 1971's. With the mods I have it is at 357 HP and 410 FLBs torque. My comment was not bashing. If I began with "poor college kid, send money" I would expect some teasing. Unless you've picked cotton, cropped tobacco or hoed peanuts from the time you're 10 till you get out of high school you don't know what work is. Remember, the only difference in men and boys is the cost of their toys.

i really wasnt talkin about you in particular, but others on a couple of the other boards, manlly other forums like the fourth gen forum. sorry if i offended you.

i would still like to know if the LT1 injectors would support a turbo engine though.

thanks
anthony

Just out of curiosity, what is the diffrence between High and Low Impedence for injectors. You can be technical about it.

Oh and 72LT1Vette, I'm 23, I know what work is. That speaks for a lot of other guys my age. Not all of us chose the college route in life and are happy with that. YOU ARE NO ONE TO JUDGE!!!!

I was quite irratated by that. Sorry guys.

I too thought that all these injectors were universal and should be a direct bolt on. I realized that was not so after installing them and seeing gas squirt out the injector holes. I bought the 24 lbers from Summit. when I removed them they were indeed a tad shorter than the stock thus resulting in them not sitting far enough in the injector holes on the base so that the orinbgs could make a seal. By grinding down the fuel rail posts I got the injectors to seat properly in the holes. Don't ask me why mine didn't seat properly but maybe these are borderline and mine were just over the line. Actually when I was doing research on this exact issue a found a few posts related to this exact issue and found the fix as well. So there!!

high impendence means that it takes less power to fire the injector, but it is not as accurate, low impendence means it takes a butt load more Voltage to fire the injector, but it will fire crisply and cleanly. that is the way it works with other electrical components, so i figure these injector solonoids would be tge same.

thanks'
anthony

Exactly. Low impedance means more current (I=V/R) which means the magnetic fiel;d increases by B=. So the pintle moves faster and everything is a lot more accurate.

Lets put it this way, if you put Low impedance injectors in your TPI car your gonna fry the injector drivers in the ECM...

Trust me....

i just put 24 lb injectors in mine with the 305 chip still ,till the other one comes in and no leaks and runs fine.

To wrap this up thread up. The injectors are in and they work great. I cut off about 1/4" of material on the support towers and that did the trick. I did a test prime of the system to make sure there where no leaks and all of them checked out. I got the TPI all back together, set the fuel press to 39psi, and the car idles smooth and the throttle response is much crisper. Ed is right, I need to get some prom burning equipment to change my injector constant so that it does not do any damage to my ECM or the injectors them selves. That is the next thing on my list and I may just warm up the old credit card to get it so I can have it and start learning. I have read through Ed's sticky post on ECM burning and I am about to dive into it. There are some other things I want to adjust on the ECM so I am going to drop the $250-275 and get started. I should have pictures of the whole thing on my cardomain site sometime this week.

Hey 72, you have a really nice car. I have always been a fan of the "shark nose" vettes. My comment in my sig is kinda for a laugh but it is true. I always have people telling me all these things I should do to my car and I always ask them, would they like to make a donation? My posting in response to what 72 said earlier was not intended to be start of a war of words but just a clarification of what some people might think of me. You are cool in my book 72

I would suggest you buy a UV light along with the PROM burner. Saves money on chips in the long run. Start with the simplier math functions. Some of the more advanced trig function settings can create weird happenings. I can testify to it personally, but after a while it gets easier. GOOD LUCK with your car and education. My generation has a saying "Illegitimate Non-carborundum". PEACE!

So, does anyone know for sure whether the LT1 injectors zare low imp. and the TPi's are high imp.? I am getting ready to buy some #24s and I want to make sure that it will not damage anything. I have not got my PROM burning equip yet, but I need new injectors as mine are leaking.

Tim

Hey Ringmaster, you might want to email Rich at Cruizin Performance. He should be able to tell you anything you want to know about injectors. I think i am going to send my old 22lb injectors off to him to let him prof clean them so that way I always have a good back up set.

Thats not why, and thats not correct either. HP ratings have never been at the rear wheels, its always been at the flywheel.

Hey Madmax, THE 1972 WAS RATED AS "RWH" AND IT WAS TO REDUCE INSURANCE RATES BASED ON PUBLISHED HORSEPOWER RATINGS. I know, I own a 1971 and a 1972 LT1/HO and have read all the books. I left the 71 original and bought the 72 to play with. The 1971 and 1972 with the LT1/HO engines have identical 350CID/330HP engines measured at the flywheel. The 1971 console decal states 330HP 9:1 compression /360 Foot Pounds of torque. The 1972 console decal states 9:1 compression/360 foot pounds torque, no HP rating. Same solid lifter cam, same everything except HP rating.

No, it wasnt. I cant count how many times this same subject comes up, and how many people just have the wrong story as to what really happened. You can do a search on the subject on this board if you wish, some people have an even more exact explanation of the goings-on than I do.

Before: SAE (gross) HP ratings:
Measured with no accessories, headers, tuned carb+dist, everything they could get away with to get more HP out of the basic block. HP measured at the flywheel.

After: SAE (net) HP ratings:
Measured with all accessories, exhaust manifolds, etc. to give a more true reading of the actual engine's HP. HP still measured at the flywheel.

GM had nothing to do with gross or net HP ratings, GM, Ford, and Chrysler changed from one to the other. SAE is Society of Automotive Engineers, not GM. Its just a standard set of 'rules' that are supposed to be followed to call the test results per SAE standard.

Want more proof? Take a look at any SAE gross and SAE net HP rating for the same vehicle and engine combo both pre and post 1972. Tell me what you see for HP for auto trannys and manual trannys. I'll bet ya a dollar there arent 2 ratings that differ based on the tranny difference alone. If it really was RHWP, the numbers would be different simply because a manual does not eat as much power as an auto.

And that would make your generation several thousand years old. Illegitimi non carborundum, which roughly means: Don't let the bastards wear you down. Pax.

I used 24lb injectors from a 95Z also, they seemed to fit and run fine, except I get a fuel smell whenever I drive it. Perhaps that's the no charcoal canister..

Well, fellows, I went ahead and got the facts from Rich at Cruzin Performance. He was nice enough to lay it all out. Here is the email he sent me.

Hi Tim,
Yes, you can use LT1 injectors as replacements for your car.
LT1 injectors have a slightly lower resistance than the original injectors
that would have come in your car but they are still "high impedance"
injectors (or are sometimres referred to as a "saturated" injector).

The original injectors in your car would have a resistance of approximately
15 ohms and the LT1's will be around 12 ohms.

A "true" low impedance injector (also sometimes referred to as a "peak and
hold" injector) has a resistance of approximately 2 ohms and cannot be used
as a replacement for a high impedance injector without damaging the injector
drivers in the ECU.

Hope this answers your question. Sometimes there is a lot of mis-information
spread on the various message boards. I'm glad you took the time to ask.
Better to be "safe than sorry".

Rich J.

72LT1Vette.... Where is your dyno graph? There is just no way you make that much power with that small of a cam and that low compression. If you had that kind of power, I would be glad to race you and have you hand me my ***. You are a better man than I to get that amount of power out of those mods.

For the topic poster. Good work. Way to think your way out of a problem!

Here's a couple of links from the MSD page that backup what Rich found out...FYI
http://www.msdignition.com/fuel_1.htm
http://www.msdignition.com/fuel_3.htm