[Joe-Touring]

Just to contribute, I just changed out a 5 yr old stocker type Carter pump for a Carter Super Street. I’m currently running a 326 and had some issues, mainly heat soak/vapor lock, I believe. If I was at a stop light for a minute or two, and then took off full throttle, a couple seconds after I shifted into 3rd it would fall on its face. Same thing when I took it to the strip for the first time last summer.

I have a gauge on the inlet of my Qjet, at idle it would bounce between 5-7 psi. With the new pump it is almost rock solid at just under 6. Unfortunately I still have 5/16” fuel lines, I replaced em when I first built the car, before I knew better

Figured I’d chime in and say that even a 326 showed some improvement with a better pump.

[Bill S]

I really appreciate all advice and thoughts on the fuel pump upgrade.
I was thinking back to when I first became interested in putting Pontiac power in my bird ( I used to have a Chevy 327 in it from a $50 junk car ! when i was young), and had no internet. All we had was magazines, the local speed shop (which their main mission was to SELL you something) and limited books. I dug up my old Pete McCarthy book last night. Page 91 "FUEL-ISNESS" paragraph says it all. I like how at the end he states "Each time I hear a street racer complain about his car just dying at the top of second gear, my eyes start rolling again".

[78w72]

Originally Posted by Joe-Touring

Just to contribute, I just changed out a 5 yr old stocker type Carter pump for a Carter Super Street. I’m currently running a 326 and had some issues, mainly heat soak/vapor lock, I believe. If I was at a stop light for a minute or two, and then took off full throttle, a couple seconds after I shifted into 3rd it would fall on its face. Same thing when I took it to the strip for the first time last summer.

I have a gauge on the inlet of my Qjet, at idle it would bounce between 5-7 psi. With the new pump it is almost rock solid at just under 6. Unfortunately I still have 5/16” fuel lines, I replaced em when I first built the car, before I knew better

Figured I’d chime in and say that even a 326 showed some improvement with a better pump.

Thanks for the info, 5/16" lines are a huge restriction for any carb'd engine or pump, not surprised you had some issues with a stock type mech pump even on a 326 with that size line, upgrade the lines and it would probably do a lot better. The carter SS pump should work "fine" just going to 3/8 line for your lower HP street car.

HWYSTR- No offense taken or given on my part, sorry for using the word "fine", its a general term that means no problems or issues, doesnt always have to be on/off for things like this. Every car/engine combo is different, saying "all mech pumps dont work" is not true, its only for higher hp cars usually doing mid 12s or faster at the track that run into the issues we hear about with starvation.

If I decide to go faster than low 11s at 121-123mph I will upgrade to tanksinc set up & will report back if that fixed my occasional problems at the track or picked up .2-.3 tenths that some claim going to electric pumps. That would be awesome & put my stock E-head Q-jet street car into the 10's!

[Formulajones]

I think most of you guys here are just street cruisers that want to get from home to the dairy queen and back. There are a few of us that are more serious about performance in our street cars. That's where I think the differing of opinions and different results are coming from.

[Formulajones]

Originally Posted by 78w72

If I decide to go faster than low 11s at 121-123mph I will upgrade to tanksinc set up & will report back if that fixed my occasional problems at the track or picked up .2-.3 tenths that some claim going to electric pumps. That would be awesome & put my stock E-head Q-jet street car into the 10's!

Honestly if you're going 121-123 mph, that car should already be in the 10's. That's easy 10.80's with a decent short time. That tells me that your short time is lacking and most likely the biggest reason why you're getting by with a mechanical pump at that HP level. Once you get that thing to launch like it should I think you'll quickly find out why I, Highway, and Cliff are telling everyone mechanical pumps are going to be an issue, and Cliff explained it pretty well in his recent post so there is no reason to rehash that.

If it makes ya feel better, you already have a 10 second car, ya just gotta work on that 60 foot.

[78w72]

Originally Posted by Formulajones

Honestly if you're going 121-123 mph, that car should already be in the 10's. That's easy 10.80's with a decent short time. That tells me that your short time is lacking and most likely the biggest reason why you're getting by with a mechanical pump at that HP level. Once you get that thing to launch like it should I think you'll quickly find out why I, Highway, and Cliff are telling everyone mechanical pumps are going to be an issue, and Cliff explained it pretty well in his recent post so there is no reason to rehash that.

If it makes ya feel better, you already have a 10 second car, ya just gotta work on that 60 foot.

I agree 100% it could or should be in the 10's, I mentioned the details on the car briefly before but try not to hijack other people threads with my cars info, this thread has surved its purpose for the OP so heres some quick info on my car & why its not in the 10's.... & I definitely dont just drive to the dairy queen!

Mainly its not a dedicated drag car or set up for drag use, I go to the track for fun on test & tune days just to see what my cars will do, the suspension isnt geared for drag use, its a very stiff PTFB kit more designed for auto-x use, so the launch & 60ft is far from ideal. I have to launch off idle & roll into the throttle otherwise the MT drag radials break free very bad & the run is lost.
It usually will do a full run and that gets 11.2-11.3's but 1-2 times out of 5-6 runs it will cut out some about half track but still pull high 11's. I am very happy with the times for this combo & really only expected to break into the 11s, but thanks for the encouragement, knowing there is 10's in it does make me feel better!

Just to be clear, I agree a good E-pump is best for this type of car at this power level, not trying to claim otherwise... my comments above are about the very vague statement that all mech pumps dont work, was just trying to clarify that they do work for the majority of average street cars below about 375-400hp. My current 78 TA proves that & so did my old 78 TA in the 90's with a mild cam 455 & 3.90 gears that ran with or beat cars that came direct from the dragstrip with mid 12 time slips, it had stock type pump & lines but had a holley double pumper. Mech pumps do work... it all depends on the car/engine.

[Formulajones]

Originally Posted by 78w72

It usually will do a full run and that gets 11.2-11.3's but 1-2 times out of 5-6 runs it will cut out some about half track but still pull high 11's. I am very happy with the times for this combo & really only expected to break into the 11s, but thanks for the encouragement, knowing there is 10's in it does make me feel better!

Ah okay, even that sounds like it's still likely running into fuel delivery issues even on an easy pass. The not launching hard helps to band aid it but still appears it does sometimes run out of fuel down track. Would be nice if you had a fuel pressure gauge visible during the occurrence just to verify and be sure but that does sound like a classic example. I agree, A bigger electric pump out back with some 1/2" line would most likely benefit your car.