Fuel Injectors

[Dave's_88]

I need some advice on injectors.

I currently have the plenum off of my '88 (changing the EGR valve as well as a few sensors) and need to "fix" the injectors. I'm pretty sure that they are not operating at 100% I live in the Austin, TX area...I haven't found anyone yet that can service, test, clean the injectors. However, I have been leaning towards buying a new set just to be safe (I realize they are pricey).

Here are my questions:
1. I was told by a mechanic that the '88 offered 2 different original brands of fuel injectors; Lucas and Bosch. Besides the extreme difference in cost, what *is* the difference and can one be substituted for the other (if I have Lucas can I switch to Bosch or vice verca).
2. I've been told that the Ford SVO 24# injectors are both cheaper and out perform the stock GM's. Is this true? What is the downside to doing this? Will the wiring harness/ECM fit and recognize the injectors?
3. Are my stock injectors 20#, 22#? What would 24# injectors do if I installed them on an otherwise stock engine?

Thank you

 

[grumpyvette]

injectors

If your going to change injectors change to the 30lb size I did this on my 1985 tpi vette that has a dual 58mm throttle body and a ported and polished intake with oversize runners and accel base this change helped the low and mid-range torque a great deal as before I changed from the stock 21 lb injectors the engine ran very lean. the stock computer worked fine with the bigger injectors and after I got a custom chip it really woke up the throttle response. the stock size was picked mostly for fuel economy and emissions, and yes the ford injectors work but I got mine from TPI-tech 1-904-437-1165 they have 30lb size for $280.00 for 8 and 24lb size for $260.00 for 8 if you need your old ones cleaned they do if for $10.00 each

 

[Jim]

Dave
First of all #30 injectors and a 58mm TB are way to big for an L98 with a modified intake, don't go there. I have SVO #24 injectors in my 90 and there are no changes required to install them, just pop right in. Now having said that! I now have a fuel smell in my air filter so I know it's running rich with the larger injectors so I need to work that issue and I have been told that you need to increase your fuel pressure with the SVO's of which I haven't done yet. Accel makes a BOSCH type #24 injector and they sell for the same price as SVO's $230 vs GM's at $480. Hope this helps. Jim

 

[grumpyvette]

injectors

jim, dave, I dont know how long you have been modifying tpi engines but saying that a 30lb injector is too big is incorrect to be polite! the cpu in your engines control computer controls the pulse width (length of spray time) to match the imput from the sensors on the engine so a 30lb injectors pulse width is going to be shorter at idle than the stock injector but since the stock system was ment to turn only 5500rpm and the manifold was designed for a 305 cid engine your stock set up is way under what your 350cid engine can handle! your not dealing with a carburator here this is a dry flow system that can not possiably flow enought in stock form to feed the needs of the engine, thats why the whole system seems to run out of power at about 5500rpm , the flow potenintial of the runners is way less than the stock heads as is! and your stock maf sensor on the engine will only flow about 630cfm if its not had the screens removed and the heat sink fins shortened. you can get by with a 52mm throttle body on a slightly modifyed L98 just fine but the system will require you to go to a 58mm later if your serious about getting the most horse power available from your engine(why buy (2) throttle bodys) once you change to a good deep breathing cam and headers the bigger throttle body and injectors are mandatory as the stock injectors can not support even 400hp without running very lean and possiably burning pistons!you must not think of injector sizes like jets in a carb. or throttle bodys like carb.sizes injectors flow only as much as the computer tells them to ,up to there max ratings and while it is possiable to get too big a throttle body,the L98 tpi NEEDS ALL THE FLOW IT CAN GET!

 

[vigman]

You go Grumpy!

I agree 100% with the grump. I'm running the ford ones... no problems... I do need a bigger TB & my stock one is leaking.. I did make the mistake of NOT changing the OXY sensor and I was running a bit rich due to the funky sensor... my only problem now is HOT starts, I think my cold start sensor stays on longer than it needs to be,

Mike