1050 conversion issues
 

So i converted over to e85 because of gas prices. The motor ran great on 91.

Its a 461ci 11:3 to1 street car.

Im curious to know if anyone has changed over like me and has had any of the problems im having.

One is i cant seem to get the car any richer then 12.3 AFR. I would like to get down to 11.8-12.0 at the leanest . I have #8 AN line feeding all the way to the bowls. carb has 90's in the front and 107 jets in the back . its a dead headed holley HP 125 pump . This motor is in the ball park of 650-670hp . Anyone have any ideas on whether or not its the pump not having enough ability or maybe the #8 is to small? I know that the fittings for the #8 measure around .330 thou ID. So im thinking having a bunch of these in the line that measures .490 id could be a potential choke point ?

Second problem is: It bogs on a quick stomp. Doesn't matter if its from a dead stop or from sec gear cursing down the road it will happen . i have a .045 squirter in the front with a 50cc pump . Back i have .050 squirter with a 50cc pump . Both have the hollow screw. The old setup on 91 octane had a .035 in the front and a .045 in the back. It worked great. It was all business ... So im not sure whats going with the change ..

Other then that it screems. Im super happy with it.

If anyone can help id really appreaciate it..

Thanks...

Is the 125 number the gph? If so I'd think that may be small. Add 30% to what you'd want on gasoline and that's a good starting point.

Heres the pump i have ..



https://www.summitracing.com/parts/hly-12-125?rrec=true

Yes 125 gph

I don't see the flow number vs pressure. If it had 125 gph @ your running pressure it might be enough. If it's 125gph at wide open flow (no pressure) I'd think it's iffy...
ETA: stoich for e85 is around 9.7, you may not be happy with the results at 12...

I come up with 75 gph for 670hp using e85. so 125 should be enough i would think?

Did u do anything else to the carb? Air bleeds etc? There is more to it then just jetting

80 gph @ 7psi should support it on a Dyno anyway. Gravity forces, line friction etc will probably drive requirement higher. It would be nice to see the actual pump curve for that pump.

They say that e85 need around 63-70 BSFC for every 1 hp . so i did 670hp x.70lb fuel = 469. Then 469 / 6.25 = 75.04 gph.

Just showing how i came up with the number

Yes i did.. Idle and cruising are good . Its just wot that i cant get right...

What about needle and seat? It may need to flow more huh?

Yeah i don't have a fuel pressure gauge in the car to know what it is under load..

Its set at 7psi at idle. I also have .150 needle and seats front and rear

I feel like i should have enough jet in it . So in my mind its either the fuel line or the pump . Is there something else i could be missing ?

Here's the pump curve. Looks like ~100 @ 6.5-7psi, then falls off a cliff... I think that could end up marginal under hard acceleration, but I'm no expert...

With a carburetor Does the fuel pressure fall off as you're getting down the track in general? If it does would it result to better flow ?

That does fall of surprisingly bad lol

So you're leaning towards not enough pump?

what pump would be a good up grade to get?

How do you feel about #8 lines jn this case?

Any thoughts about the bog?

I think if you can keep the #8 line full under all conditions, it should be enough. Maybe pull the lines off the carb and do a flow check post regulator? See if the results make sense for 100gph through the system, or if it's less. As for the transition lean spot, I've never dealt with alky carbs. My only experience is with EFI. I'd ask the question have you increased timing any for the E85 set up? And are you sure it's a lean stumble, and not related to needing some more timing? Also, I edited an earlier post, not sure if you saw it, don't forget about stoich for e85 being in the 9.7 range. You mentioned earlier shooting for 11.8-12 and that may hurt something.

I think a set of metering blocks specifically made for E85 would be a good idea. And a larger fuel pump could not hurt.

I have had problems with bog’s when launching at the track .
I spent a lot of time once screwing with that 3 circuit 1050 and for me the cure was a 2 circuit 1050.