Larrys T/A

I have the Ford 24lb Injectors and was wondering if they would work with a stock 350 chip. I know i need a custom chip eventually, but can i run the car for now.


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• 1987 Trans Am 350tpi, 5speed,SLP Headers,Stock 1995 Z28 Muffler, Gutted Cat,Compucam 2030 429 452 Lift & 204 214 Dur.,TbBypass,Ported Plenum,AFPR, SLP LCA,SFC. 13.86@96.8 with 1.96 60ft

Scott C

From what I understand, no. The 24# SVOs are actually 26# when flowed at the same rate as GM. That's too much fuel and the only two ways to tune it down are lowering fuel pressure (not good), or adjusting for it with a custom chip or DFI. Some people say the 24# work fine, but most say no.

Grim Reaper

Scott is right. Your car MIGHT seem to run fine and you'll be able to use it as a "stop gap", but it will be way over rich. Good time to get into PROM burning.

The money you saved on the Ford SVOs will pay for the prom burning equipment, and you'll end up with a better performing car overall.

If you burn your own PROM, you just adjust the Injector Flow Constant. In fact, it is not a bad idea to bump up the fuel pressure to around 45-47 psi (that seems be a happy medium where the car gets higher fuel pressure, but don't burn out your fuel pump) and increase the Injector Flow Constant somewhere around 27-28. You will have to play with it to find a constant that gives you a nice idle and doesn't run too rich or lean.

BadSS

This is my first attempt at a modded EFI, so my EFI knowledge base is limited. I believe it depends on the combination whether the 24#SVO injectors will work with the stock chip or not. I'm running a pretty good set of heads, fully ported intake and plenum, SLP runners, pretty healthy cam, and ported MAF (that helped the idle even with the 305 chip). I was having terrible problems with idle (way rich) with the stock 305 chip (of course),, but with a stock 88 350 chip,, the car is idling near perfect (just a faction rich - not bad at all) and the plugs look perfect at WOT (46 psi), and I've never seen it make more than 2 degrees spark knock. However, I think I may be the exception rather than the norm based on pervious posts.

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86 IROC - 9.8:1 - 355, TFS twisted wedge heads, 218/228-110, fully ported GM base and plenum, SLP runners, 52mm BBK, 24# SVO, 1 5/8" Headman headers, 2.5" Dynomax, TH350, 2200 stall, B&M Megashifter, 3.23 peg leg, 245/45ZR17s on 212 Eagles
Best run - 12.53/112.4 on 26x11.5 ET Streets.

Grim Reaper

The risk you have with a larger injector (or even just higher fuel pressure) is that you are increasing the amount of fuel flowing in a given mSec. Thus you need to shorten the Pulse Width to ensure you get correct amount of fuel. That is where putting a larger Injector Flow Constant helps. That is why a 305 chip (19#) caused problems where as the 350 (22#) seems fine.

But the problem you get into (as BadSS) is alluding to, is that you can only shorten the PW so much until it becomes unreliable. With more mods, you will NEED that extra fuel so short PWs are not a problem. But on a stock motor, the shorter PWs may.

But I don't think a SVO 24# injector is too bid for a 350 TPI. The PWs should still be reasonable. And if the shorter PWs do become a problem, the solution is simple, modify the engine more.

But whatever you do, LEARN TO BURN YOUR OWN PROM. It will be the only way to get a good idle and good performance. You will have to play with it a bit, but it is quite fun. Getting a good idle is easy, getting a "perfect" idle with a "perfect" fuel map takes a little time. But the efforst are quite worth it. I am still after my "perfect" prom.

Larrys T/A

Hey guys thanks for your help. I guess i will start by saying i will put them in and see what happens. My combination now is 19lb and stock 350 chip. I've adjusted the idle and its fine but the car runs way to rich and codes 24 & 42 keep coming up. This is what Badss talks about (running way to rich) something about Pulse widths. Maybe this is why my car is running way to rich. I don't know, as you can see i'am learning. Again thanks guys. I will let you know what happens.

Larrys T/A

Well guys i put them in and bad news. The car barely started and when it did it was running with a bad miss. So i will say back to the drawing board. I think the injectors are bad (they were used), will get them tested. Thanks again for your help.

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• 1987 Trans Am 350tpi, 5speed,SLP Headers,Stock 1995 Z28 Muffler, Gutted Cat,Compucam 2030 429 452 Lift & 204 214 Dur.,TbBypass,Ported Plenum,AFPR, SLP LCA,SFC. 13.86@96.8 with 1.96 60ft

Grim Reaper

Check your fuel pressure. You may be way to high. 50 psi makes a LOT of fuel even on 19# injectors. So if your fuel pressure is high, try backing it off. I haven't re-read all the posts in this thread to see if this has been discussed already.