Will the 307 be enough?

[TurboBuickSix]

I really got to get a pump in this thing,is the 307 good enough? What are the limits on it? I don't plan on going faster than a mid 11 sec 1/4 with this car(for now).TIA I am asking because there seems to be alot of them for sale in the parts for sale section.

 

[Nick Micale]

My opinion, I would not have one in my car if it was free!

This is based upon 5 or 6 I have replaced because they either quit or did not have enough output. Go with Red's XP Plus or a 340 for your needs.

 

[Tow Man]

Go with the 340 and be done with it!! The fuel system is not the place to save a few bucks.

Racetronix sells a 340 and hot wire kit at an affordable price.

http://www.racetronix.com/Racetronix-Buick_Single_Fuel_Pump_Kit.html

 

[TClassic2]

Jack Cotton went in the 10,s @ 120something with room to spare. And unless you Specifically request the 340, he ships out 307's as the Standard high volume pump. A 307 should be MORE than enough for Mid 11's(with a wiring upgrade)!

 

[TurboJim]

JaCK also had heads/cam on his car and ran conservative boost levels, meaning, conservative fuel pressure levels. If this guy intends on running 30psi of boost, get the 340 as its bypass is set to 80psi vs the 307's which is like 60. Otherwise, the pumps are identical internally

 

[TClassic]

Whats the Fuel Pressure limit of a 307, as I called Jack for a pump shortly after I bought this car and he shipped me a 307, so....
I installed it thinking it "Should" be fine as this car will only see 11.50's or Slower!! Was I WRONG??????

 

[TurboJim]

Well, Racetronix lists the bypass at ~60psi on the 307 and ~80 on the 340. Given that, if you start at a 40# base pressure, and run 20psi boost, you're opening the bypass in a 307 and losing supply volume to the bypass. The same car with a 340 could run 30+psi with a 340.

Least that how it looks to me.

 

[TClassic]

Oh MAN, time to drop the Gas tank again....and I've been telling folks (including myself) that the 307, that ALL the Vendors are still pushing on folks (Jack, Kirbans, ATR, RamChargers,etc, ALL ship a 307 when a Customer calls for a fuel pump and dosent specify a 340!) and I used on my OLD car at 25-26PSI of Boost is PLENTY!!

 

[TurboJim]

Well, I would call and ask first. I dont want you to do all that work becdause of my possible mis-information. Its just what I read and thouight to be fact

 

[cmokem]

I have been running 45 lbs of fp with 20 lbs of boost on the 307 with no problems. I remember talking to some guy at walbro saying that the 307 was good to 70lbs before I bought it. Didnt PTE do some sort of test between the 307 and 340's a while back??

Bob

 

[TClassic]

Originally posted by cmokem
I Didnt PTE do some sort of test between the 307 and 340's a while back??

Bob

THANK YOU BOB!! Thats where I remember reading it, it was ~about a year or so ago when they were running a Special, they did EXTENSIVE flow test comparison, and I believe, if memory serves me right, that they were so close that the difference was negligable!

OK, now maybe I Won't be dropping my tank again soon!

 

[d0n_3d]

i have a hotwired 307 from PTE on my car and i have a te-44 turbo with 50 lb injectors and i ran 23 lbs of boost on the street one time with race gas and i was WOT with no knock due to fuel starvation...i also heard that there is little difference between a 307 and a 340...just hotwire the 307 and you will be fine...

 

[TurboJim]

Originally posted by cmokem
I have been running 45 lbs of fp with 20 lbs of boost on the 307 with no problems. I remember talking to some guy at walbro saying that the 307 was good to 70lbs before I bought it. Didnt PTE do some sort of test between the 307 and 340's a while back??

Bob

I think you're thkning of when they tested a 307, a 307M (I believe basically shimmed check valve) and a 340. I think they did 307M's before the 340 came out. I can call Harry and ask.

I'm not trying to stir the pot, jut trying to make sure you're making an informed decision. Believe me, it desont matter to me, its not my car, I just hate to see you hurt it.

 

[steve hughes]

I have run a 307 as fast as 10.90 with 50's with 80 psi showing on the gage at wot. Technically it ain't possible. 11.50 with a 307 is not a problem.

 

[Racetronix]

Originally posted by d0n_3d
...i also heard that there is little difference between a 307 and a 340...just hotwire the 307 and you will be fine...

I have covered this topic too many times to mention here on TB.com so I am not going to get into the details again. The armature in the 340 is more effecient and will draw less current for a given load / output than the 307. The bypass pressure of the 340 is higher than that of the 307. For the average $10.00 difference between them why even consider a 307?

About two plus years ago the 307 had the same armature as the 340 but not anymore. It was common practice to shim the bypass valve on the 307's to extend their operating pressure. This might have been OK back then but not now.

Jack
Racetronix:

Tech info that I have posted can be found by using the search engine on the forum. There is also good info to be found on www.gnttype.org.

 

[d0n_3d]

well i don't care whether or not the 340 flows more...it's the fact that you can run mid to low 11's with a hotwired 307...i don't experience any leaning out conditions with my bigger 50 lb injectors and bigger te-44 turbo running 23 lbs or more...fact is the 307 is a good pump unless you want to run your car seriously fast...yes then get a 340 pump or a double pumper setup

 

[Tow Man]

Well, I don't think anyone suggested that everyone with the 307 should throw it in the trash can BUT, if you are in need of a new pump, why not just go with the 340?

Is the $10.00 difference that big of a deal? I spend more than that on coffee a day

 

[TurboJim]

Originally posted by Racetronix
I have covered this topic too many times to mention here on TB.com so I am not going to get into the details again. The armature in the 340 is more effecient and will draw less current for a given load / output than the 307. The bypass pressure of the 340 is higher than that of the 307. For the average $10.00 difference between them why even consider a 307?

About two plus years ago the 307 had the same armature as the 340 but not anymore. It was common practice to shim the bypass valve on the 307's to extend their operating pressure. This might have been OK back then but not now.

Then the info you got needs to be updated on yer site Jack as I am misinforming using that as a reference. Copy/pasted from your own site:

The Pumps

Walbro Fuel Pumps have set the industry standard in high-performance. Walbro pumps are QS9000 certified and are used as OE equipment in many production performance vehicles such as the C5 Corvette. Walbro's gerotor design is able to maintain high pressures while providing high volumes as well. This is done by squeezing the fuel out between two gears instead of pushing it like most factory vane pumps do. (i.e. factory TR pump). This positive displacement design makes high-performance Walbro pumps small, light weight, quiet, efficient and reliable. The Walbro GSS307M and GSS340M are exactly the same piece for piece internally except for the internal pressure safety bypass. Based on our own tests and engineering documents provided by Walbro we recommend the GSS307M for applications with a maximum operating pressure of 60PSI. On a Turbo Regal with a base fuel pressure of 40PSI a Walbro GSS307M is acceptable up to about 20PSI of boost.
If you plan to run higher base fuel pressures and / or higher boost levels Racetronix recommends the Walbro GSS340M. The GSS340M is the perfect pump for serious performance minded racers and is capable of supporting high fuel volumes at pressures well exceeding 80PSI of fuel pressure.

 

[d0n_3d]

at the time i bought my 307 from PTE (one year ago) it was on sale for only 99 bucks...the 340 was going for 140 bucks so i decided to go with the 307...most anyone else would have done the same thing...at the time it was said there was minimal difference between the two pumps except the 340 flowed a tiny more fuel...

i am personally not gonna go through hell again dropping my gas tank and putting in another fuel pump if i don't have to...the 307 pump hotwired does a great job for me...

 

[Racetronix]

Originally posted by TurboJim
Then the info you got needs to be updated on yer site Jack as I am misinforming using that as a reference. Copy/pasted from your own site...

Thanks for the reminder. It is sometimes hard to keep track of all the old info out there. That ad was put together just around the time the changes were being made to the GSS307 pumps. Since then Walbro has been somewhat more forthcoming with information.

Sorry for the confusion. Everything should be in order now?

Jack
Racetronix