if you are having return issues now you will have bigger return issues with E85

one of the last setups i did on E85 had -8 feed and -8 return, the past lightning we did has -10 feed and -8 return

for cocaine ill have -12 feed and -10 return



also most pumps dont like to be over 60 base to begin with so raising the pressure for the injectors to get larger will only skew the pumps output... Its preferred to run base fuel of 43 ish whenever possible on normal fuels


also look into max fuel pressure for injectors to handle, some dont like to be over 90

as for circle D some of the faster cars and trucks have circle D converters

George, I was specifically waiting for your input.

My current fuel is E50. I'm going to just go to straight E85 for maybe a hair more safety margin on a stock engine.

I would lower the base to 3 bar, but as you already know my 1000cc injectors are small for E85. So 58 psi base is a compromise, but two 450s should be able to still flow a lot at 78 psi.

If I have to go to aftermarket lines I will use -10 for feed and return.....however of note, Fragola -10 lines are only .500" ID.

If you're running a pressure regulator, your pressure delta should be constant. So whether the pump pressure is 90psi or 45psi, the injectors will still see 58...assuming you set it to 58 with atmospheric pressure in the manifold.

Fragola is junk IMHO, not a fan of their product, had to use it as customer supplied it for that lightning and 80% of fittings seep some, and a few snapped with lube trying to make them, others stripped

havent looked into what the 450s are capable of but we just installed them on another lightning and we run base of 43 so we have room to go.... Most pumps dont like over 60 base.... Youll see them become unstable in drop fuel pressure and try to recover during the run

if you plan to then log fuel pressure during the pull to make sure youre safe, and make sure you log it for a 1320 pass as that much strain on the fuel pumps can show its ugly face fast compared to a dyno pull

IMHO your return should be -8 if using e85 just based on the volume of fuel you need to run and for it to bypassed

I've had major problems with fragola that have nearly made me go insane.

In fact I was just assembling a fitting yesterday and the damn thread stripped and I had to junk it. I had major problems with seepage (and some which actually would drip fuel) from the fittings as well that was blamed on me not tightening the fittings enough or putting oil on the flare.

The stock return line goes inside the fuel pump module and dumps at the bottom of the bucket.

Worst case for a regulator would be with the engine off and pressure set at the base pressure minus deep decel pressure (14.7psi at max, would be pure vacuum inside the engine). So if you have a 58psi base pressure, if the regulator will hold down to 43psi or so then its not a return issues. I wouldnt worry much about rich decel.

Eh, probably enough power there for it. I went from a cutout 6ft under the truck to a 2' dp out the fender. Boost or power did not increase, but spool time decreased noticeably.

That 25% slip doesnt sound right...assuming you meant 6413 in 3rd gear with a 29.5in tire. With no slip 129mph would be 5900rpm. Slip would be 100*[Engine_rpm - trans_input_rpm]/[engine_rpm]. My math shows 8% for your numbers, which is fine in my book (ie, not worth upgrading). Locking might gain you a few mph, but isnt worth it in my opinion.

Use the spreadsheet I made in the fuel system.

114lb/hr@4bar at 95% IDC would support about 860rwhp (550L/hr). Dual 450s at 85psi flow about 587L/hr (this is 85-58=27psi of boost), so you should be good there. At that flow rate through a 3/8" line you will have about 2psi drop in the fuel line, so you are still fine. I dont know about the stock fuel filter, but even if you have a 5psi drop in pressure you are still fine to 20psi of boost.

his slip is more then 8%

a 30" tire with 410s and 6400 rpms will trap much higher then 126 mph in 1:1 ratio

he should only be around 5800 rpms if setup had no slip
he should be around 139 mph at 6400 rpms with his 410s and 30" tire factoring in zero slip





also unless your not maxing out the 4" exhaust then a cutout wont gain ya much, however if the 4' exhaust has alot of bends then it could gain ya some


i know on 12 psi i gained 10 rwhp opening cutouts on a dual 3" exhaust from when i had twins. the cutouts were right under the cab vs the exhaust exiting out in front of pass rear tire

Gonna make me do math arent ya?

So with a 1:1 trans gear, 4.11 rear gears, 6400 engine rpm, and 29.5" tire that is linear velocity of:

[(6400/4.11)*pi*29.5/(12*5280)*60]=136.66mph.

His real speed was 125.9mph

125.9/136.66=0.9212 then mulitply by 100 to put it in percent

That is 92.12% of ideal speed, so 100%-92.12% is 7.88% slip.


My downpipe was 5", so I wasnt expecting much with the fender exit, I mainly just wanted to be cool and loose the weight of all the exhaust. I was still suprised it made such a difference in spool time.

I'm trying to understand why there is such a discrepancy between your math (which looks legit) and the Wallace racing calculator (where I got the 25% number).

Also, if all I'll gain with shorter exhaust is spool time, then I'm okay currently. Spool is one thing this setup doesn't have a problem with.