[ta man]

Originally Posted by AG

No track runs just WOT through the gears on the street with an AFR meter.

Big difference in the amount of G force...

[Formulajones]

Originally Posted by RocktimusPryme

FWIW, I do think the pumps will sometimes get blamed for otherwise deficient designs. I had all kinds of trouble with my RObb Mc 1100. Setup exactly how he wanted. But I think some of the issue could have been the basic stock replacement tank and running away from the sump.

When I went electric the tank came with baffles. Which may have been the real fix for me. Hard to say. The catch 22 of it is, if you are going to buy a baffled tank why wouldn't you do an in tank pump. A basic cheap and reliable walbro will supply enough fuel for a carb with a return regulator 5 times over. And be significantly cheaper than the baller mechanical pump.

I think it's also that electric pumps at the back of the system are excellent pushers and not effected as much with G-force when launching the car. Couple that with the baffling like you said and you have a delivery system about as good as it gets.

One of the things I always did with my stock mechanical pump systems running stock lines, trying to get the fuel supply as good as I could, was to remove the pickup in the tank and solder in a new 1/2" pick up tube. Then I would install the largest sock I could find. A big player is the pickup. The pickup tube should always be larger than your feed line for best results. Stock stuff isn't. I was doing this long before RobbMC came out with the 1/2" pickup sending units.
I actually found a certain application from GM that had enormous socks. I think it was a truck application, and bought a dozen of them. Then I'd modify the hole for the larger pickup. Still had to always run the tank at least 3/4 full at the track to avoid uncovering it.
Some guys just eliminate the sock all together but since my cars are always street first, then race, and see 99% street miles, I wanted the sock in place as an extra precaution to keep junk out of the system.

In the end though it was a lot of work, effort, and time to tweak on the system to just get a mechanical pump setup happy, and it would still only get me so far. The in tank electric pumps just became a better solution, and with so many companies and options making them now for the classic cars, it's as easy as plunking down the money and bolting on the pieces.

I was never really doing pusher pumps along with the stock mechanicals. I just never liked the excess baggage on my cars or worrying about remembering to turn the darn thing on. It was either mechanical, or I'd remove the mechanical and run a Mallory 140 out back. But that also became a reliability issue.

We're talking doing this stuff decades ago.

These days I do none of that anymore. Building a car, I just go right for the Tanks Inc setup, put the pump in the tank, 1/2" lines feed and return, even on a 400 HP application. Then I can go 500hp or 1,000hp, carb or EFI, and the fuel system doesn't care.

[ta man]

I've seen my fair share of "dairy queen" cruisers with engines that should make 500 hp plus fall flat on their face at the 1/8th mile at the dragstrip. The usual cause is a mechanical pump.
I shake my head every time I see these threads. Guys will spend countless hours planning their builds...long cam discussions..trying to squeeze extra power out of their builds and then run a mechanical pump on a higher horsepower build. Doesn't make sense to me..running an engine lean isn't good.

[STEELCITYFIREBIRD]

Is the old pump a sealed stock or bolt together aftermarket?

Pics of pump may help in identification, better brand stock aftermarket replacements usually have # and manufacture ID on them.


What is wrong with current pump?

[77 TRASHCAN]

Skip, So your 10.99, was with that last fuel system you spoke of?

[TCSGTO]

The 1100 RobbMc has worked for me to sub 1.5 60’ times and sub 11 sec et’s. Running a -10 from the bottom of the tank, -08 to a large port Holley regulator, -08 to the carb inlets, and .130 needle and seats. Not a Q-Jet though. The fuel pressure is turned up to 12 at the pump outlet and it gets regulated down to 6 at the carb.
Interesting about the RobbMc dropping to 3psi for someone. I’ve never checked pressure down track, maybe mines dropping too?

[Skip Fix]

Yep 10.90s with the original stock sender/pickup dead headed Mallory 140 pump then -8 to regulator and carb. Although the 10s are with a Holley with two bowls and needle/seats vs the Q jet.

[RocktimusPryme]

Originally Posted by ta man

I've seen my fair share of "dairy queen" cruisers with engines that should make 500 hp plus fall flat on their face at the 1/8th mile at the dragstrip.

Mine was about 100'. Its a Q jet though, a Holley with two bowls might have bought me more track.

I had the Robb 550. Fell on its face with street tires. Switched to the 1100 with a vapor return. That made it down the 1/8 on street tires. But when I put drag radials on it this year, the falling on its face returned. I may have been able to patch that issue if I had run the tank slap full.

At the end of the day I bought a Tanks inc LS swap tank used locally, converted my Robb MC regulator to return style, and the problems went away. At least in the 1/8th.


I think the fallacy is that its easy to feel like staying mechanical is cheaper. For me, and for others with similar experiences, I spent more time and money trying to get the big mechanical to work, than if I would have just gone with the in tank pump to begin with.

[Formulajones]

Originally Posted by TCSGTO

The 1100 RobbMc has worked for me to sub 1.5 60’ times and sub 11 sec et’s. Running a -10 from the bottom of the tank, -08 to a large port Holley regulator, -08 to the carb inlets, and .130 needle and seats. Not a Q-Jet though. The fuel pressure is turned up to 12 at the pump outlet and it gets regulated down to 6 at the carb.
Interesting about the RobbMc dropping to 3psi for someone. I’ve never checked pressure down track, maybe mines dropping too?

I've talked to Mike, a buddy of mine, about his combo and we've raced together while he was experiencing those issues.

It's really a basic combo. 9:1 455 with ported iron D-ports that flow 220cfm, solid flat tappet cam, warrior intake with a 1050 dominator. 400 turbo with an off the shelf Hughes converter, and 3.73's. Has 1/2" lines and a big RobbMc mechanical pump. I don't remember what he had it regulated to but he was having issues by half track with fuel pressure drop and down to 3 lbs. before the finish line. He eventually went in tank pump I believe and the car did eventually go lower 11's. He's now building a turbo system for it.

Here is a pass with the 3 lbs. fuel pressure. Can't hear the car laying over but it was certainly having some sort of fuel issues.

https://youtu.be/TWZBq9aM1bs

[421mike]

Originally Posted by tom s

FWIW,the engine in my 63 lemans was a 550 HP 421SD and had no issues at the track with 2 750 AFBs with the street pump but was being pushed by a electric in the back.The electric was only used to prime or at the track.Tom

Tom what size fuel line from tank ?

[Tom Vaught]

I ran 11.55 with my 64 GTO many years ago with a pair of Holley Blue Pumps, I believe, it was a long time ago. Know the time and the mph 117 is right. At some point I had moved to the Mallory 140 pump and the much better Holley 7/16 flow ball regulator. The small holley regulators were very low flowing pieces, (The system was "dead-head" like Skips set-up).
On the street a basic 6 valve fuel pump and the pusher pump worked ok for the tires on the car.

I really like the Tanks inc stuff with the baffling in the tank and the ability to run "High Flow" Fuel pumps in the tank.

Tom V.

[TCSGTO]

Originally Posted by RocktimusPryme

Mine was about 100'. Its a Q jet though, a Holley with two bowls might have bought me more track.

I had the Robb 550. Fell on its face with street tires. Switched to the 1100 with a vapor return. That made it down the 1/8 on street tires. But when I put drag radials on it this year, the falling on its face returned. I may have been able to patch that issue if I had run the tank slap full.

At the end of the day I bought a Tanks inc LS swap tank used locally, converted my Robb MC regulator to return style, and the problems went away. At least in the 1/8th.


I think the fallacy is that its easy to feel like staying mechanical is cheaper. For me, and for others with similar experiences, I spent more time and money trying to get the big mechanical to work, than if I would have just gone with the in tank pump to begin with.

What lph rating pump and what size feed/reed and return lines are you guys With the intank pumps using?

[Tom Vaught]

I am going to use a 450 liter per hour fuel pump because it is rated to allow ethanol fuel use constantly. We have a lot of corn in the fuel in the Detroit area.
The 400 liter pump which some are using is not rated for ethanol fuel.
I had two of the non rated production electric fuel pumps fail on me in two vehicles over time with the corn/fuel we use. Not going there again.

Tom V.

[RocktimusPryme]

Originally Posted by TCSGTO

What lph rating pump and what size feed/reed and return lines are you guys With the intank pumps using?

Mine is the tanks inc GPA 6, 400 lph. Which is waaaaay overkill for a carb. But as I mentioned, I bought mine used from a guy who had an LS swap.

Im using -8 to a 1/2 stainless feed line, and -8 return all the way back. The regulator is the same Robb Mc regulator I was using when I was mechanical, but it was converted over to a return style.

[tom s]

1/2 in from tank to the Carter,3/8 from the pump to both AFBs.Tom

[tom s]

I built the Tempest 22 years ago,did not have a mech pump on the engine when built.Was out for a drive and the elect quit stranding me on the road.Next day it when back on and never looked back.Correct the wiring issue but kept thr front one.Tom

[Formulajones]

I always go to the 400 LPH pump in the Tanks Inc deal, and I run 1/2" feed and return lines the full length of the car, with an Aeromotive 13301 regulator. I've installed several of these for people as well as our own cars for years without a hiccup.

It'll support over 1,000 hp so it's overkill for most street stuff, but the fuel pressure will never flinch.
This setup is on dad's 724hp GTO and I use it on my 600hp Chevelle as well. And when we converted both cars over to Holley Sniper Stealth setups, all I had to do was swap the spring in the regulator for EFI pressure and it's ready to rock.

You can tame this setup down with a 255 pump for those at or under 600hp if you wish, but for about a $60 difference I just prefer to step up to the 400 LPH pump and call it done for anything I throw at it.

Matter of fact, my 70 bird that I daily drive still runs it's stock fuel system with an original AC delco mechanical pump that is now 21 years old. I've gone 13.10 @ 104 with this setup (corrected 12.76 at 106) with a bone stock RAIII 400 in the car. I'm to the point the age on the stock pump has reached it's limit with me and I don't trust it. Rather than screw with another mechanical pump where reliability lately with me has been hit and miss (actually more miss) I really don't trust them anymore. So I'm just converting the car now to Tanks Inc, 1/2" lines, probably a 400 LPH pump, and be done with it. Totally overkill for a car that doesn't even make 400hp, but I can do any engine I want in the future and never have to revisit the fuel system.

[TCSGTO]

You guys make a convincing case.

[Formulajones]

Originally Posted by TCSGTO

You guys make a convincing case.

Well, what you have is working for you, I don't know if I'd mess with it. Unless you foresee an issue or maybe want to add an EFI setup or something, I'd just enjoy as is.

It's hard for most to get past the price point for an in tank setup and I completely understand that.

Tanks Inc tank, a fuel pump, a floatless sender, a trap door if you want one, will all set you back about $600

Then you need a $150 regulator (least that's what I like anyway) 13301 Aeromotive is $152 on Amazon.

All that's left are lines. The ethanol safe AN Nylon stuff I like to use is $8 a foot. I just buy a 50 foot roll to run feed and return the full length of the car so you're looking at $50 there. Not too bad.

The fittings get ya though. AN fittings with various 90 or 135 bends depending on how you want to run things can be $10 to $20 a piece. I usually end up spending about $100 on fittings by the time I'm done.

All and all I'm usually into a fuel system like this for about $1,000

[Tom Vaught]

The vehicle with the Tanks,inc system is Naturally Aspirated currently.
That being said, I agree a 255 l per hour efi pump would support that deal.
But I like doing Boost upgrades and if I choose to mount a Vortech Supercharger
on the front of the engine down the road, I don't have to mess with the fuel system.

I could have used a ethanol 255 liter fuel pump but again, why do the job twice.
Same deal with trying to make 1220 hp with a 1000 hp fuel system, not going to
happen and you are back changing stuff again.

The boys at Ford fought a fuel system issue with their Vortech supercharged 4 valve mustang at high rpm/hp.
They tried several things. My boss said, help them fix this deal Tom, so I put a proper fuel system on the car
for the HP needed and guess what, NO MORE ISSUES. So you need to build for your application vs assume
that what works for one guy and his vehicles will work for a different application.

Typically the advice from that guy may be fine for his application but not for your application.

I buy parts for MY APPLICATIONS, and experiences, not based on internet posts.

Tom V.

And I am sure that Tom S is happy with his fuel system and the way he drives HIS vehicles.