I have a guy I’m helping out and want to add a high speed bypass to his set up.
If anyone wants to give me a hand I’ll email them the present tune & changes we’ve made and go from there. Thanks

Have you spoke with James Monroe or Scott Offerman 358T on here?

No not yet.

Why do you want to add one?

If you don't have O2 & fuel pressure logged then it's a crap shoot/trail and error. If you got O2 and fuel pressure logged then it's easy to figure out both when and how much to take away.

BTW, your typical BBC combo, if the system was sized correctly don't need a hi speed bypass deal.

easier of you can add a air or electric valve. With air you will need electric over air solenoid to control it. You can set it off timer or rpm.

With high speed bypass every change you make in system will effect the point you have that pressure at. If you go little bigger on main it will have less pressure. If you change one or two nozzles it will effect it.

I can estimate the starting points fairly close. After that it is like Top said unless you have a data recorder. Wudeopen is also correct in that changes elsewhere interact with a poppet or diaphram style hi-speed so it is important to understand what does what.

Check your pm's

Scott

I think most all of the opinions above are right. If your pump is on the small side you will not need it even on 1/4 mile tracks. Very few will need it at all on 1/8 mile tracks. If you do go with a high speed I would go with small pill and only pull a little off the top. Tune everything for best 60 foot and ET and then see if you can pick up a few MPH on top with high speed.

My suggestion read all you can about mechanical injection and then call SCOTT to get a baseline. Most do not need a high speed and often it will just complicate things.

Data logger is a HUGE help to get tune up right as is DYNO time. My Dyno Dude is really good with mechanical injection and cat get it right quickly. One of best investments you can do is dyno.

Presently
.031 nozzles .096 pill 100psi 01/2 pump 2800da.
Cars consistent,egts are 1160.
Plugs are glassy looking with very little heat on the top threads.

quote:

Originally posted by B.C.Malibu:
Presently
.031 nozzles .096 pill 100psi 01/2 pump 2800da.
Cars consistent,egts are 1160.
Plugs are glassy looking with very little heat on the top threads.

This is a 434sbc in an altered I believe.
Decent air it runs 8.0’s at 165.

quote:

Originally posted by B.C.Malibu:
Presently
.031 nozzles .096 pill 100psi 01/2 pump 2800da.
Cars consistent,egts are 1160.
Plugs are glassy looking with very little heat on the top threads.

What 01/2 pump? Gear pump? That tune sounds a little lean to me? How much temp gain?

IMO - You should tune by ET & temperature gain on injected alcohol as its very hard to read plugs. Real easy to go in the wrong direction...

agree on et and mph.O disagree about reading plugs. Some plugs I have nevr been able to read.NGK's have always read same as egt's and bearings.

.033 nozzles will have it popping out the tubes in the lights.
.031 nozzles increased mph by 5 mph.
Pressure gauge is in the feed line of the bvalve.
Exhaust ports are carbon black.
Gains 10 degrees water temp.
Scott O is gathering info from me via email.
Car runs in da 2500 to 7000ft.

This message has been edited. Last edited by: B.C.Malibu,

quote:

Originally posted by B.C.Malibu:
Presently
.031 nozzles .096 pill 100psi 01/2 pump 2800da.
Cars consistent,egts are 1160.
Plugs are glassy looking with very little heat on the top threads.

On my car when I ran EGT the car was too fat and would not run at 1050-1100 in the 1/8 mile. Get it up to 1350 to 1400 and the car would run. I ended up getting rid of the EGT and went to O2 on all 8 cylinders. Way better.
I think it may need to be leaned out some. Forget about EGT or even O2 until after you get right tune up and best ET and then use those to keep it there.
When you get best performance then look at EGT and O2 and you may be surprised at how much you were leaving on the table.

Curly I agree.
I’m sure if it had -10 plugs they’d color a bit.
Cars repeating just trying to sneak him down into a safer consistent tune without him needing a different pump.

.033 nozzles .090 bypass = 159mph & popping out the headers at the big end.
Not much water temp gain

.031 nozzles .096 bypass = 165. No popping out the pipes.
10 degrees gain from the hit to the big end.

02 sensor will not like a zommie header.

Presently it runs 132@ 1/8 and 165 1/4.
At 1800lbs how much power do you think it’s making 650hp.
Does it really need an 01/2 pump?

This message has been edited. Last edited by: B.C.Malibu,

o2 in a zoomie isn't the end of the world. You just measure one cylinder.
What happened to the incrementals after the change? The short times coming around? It wouldn't completely surprise me to see a half pump work better with a high speed bypass. I used an electronic one in the past. It won't pick the car up a ton, but maybe you will see a mph or so. I generally use it as icing on the cake so to speak.

A simple solenoid added to system and half a dozen or maybe less will tell you if you are heading in right direction or pissing on wrong tree.
Kohler sale one for about $125 that use very little power to operate. Install it with smaller jet maybe .040 0r .050. Connect it to a timer on you delay or grid if you have. Have it open slightly after you hit high gear. If mph increases repeat with one stup up on jet. If mph decreases after cpl back up to highest mph jet. You can then mess with time you open it.

With electric solenoid you can open and close as many times as you have timers for. Down side if you are a tinkerer you need good records to keep you from screwing yourself. That is probably cheapest way you can learn that rule. It cost me a lot more to learn.He11 I need a secretary taking short hand to keep up with my ideas and tinkering.

If car does not respond then you wasted about 150 bucks plus runs. I be picture its tiny dot. That is just my opinion and the approach I would take.

Ran 130/132 depending on altitude with .033 in the 1/8.
From the 1/8 on it wouldn’t accelerate as well as the .031 .096 tune 165mph so far.

Going to larger nozzles and slowing tell you it didn't like more fuel. You also lowered system pressure. Go to FIE site and check out tune up calculator. You will see pressure changes with nozzle change. You can swap jets and see flow change and pressures. Just a suggestion to give idea of what happens when.

You could always try a ,030 nozzle setup if you have then its free if not its about 60 bucks. Like I said go try the site its free and fun. Its not perfect but so far its dang close to what I have seen system change on my cheap home made flow bench if you want to call it that. Most are not stupid enough to spend money to build something like that for the he11 of it and the fun of what if.