Q-Jet "Not Recommended" on Performer RPM Intake
#1
Q-Jet "Not Recommended" on Performer RPM Intake
So Im looking at the RPM intake for my rebuild. I also wanted to keep my Qjet and have it rebuilt. However, the documentation for the RPM states that Edelbrock does not recommend EGR-style Quadrajets on the RPM intake. Anyone have any experience with this? My carb is from 72 so it is the EGR style. Whats noticeable is that it says its not recommended and not that's it not compatible.
I would think that you could just bypass/disable the egr on the carb but I do not know too much about these carbs.
I would think that you could just bypass/disable the egr on the carb but I do not know too much about these carbs.
#3
You can't install an EGR valve on the Performer RPM intake. A Q-jet will run just fine. The Performer RPM will accommodate a spread bore or square bore carburetor. Since you would have to delete the EGR valve if you swap to this intake, you would probably want to retune your ignition curve and carburetor jets / rods; however, it wouldn't be necessary.
#4
#5
You can't install an EGR valve on the Performer RPM intake. A Q-jet will run just fine. The Performer RPM will accommodate a spread bore or square bore carburetor. Since you would have to delete the EGR valve if you swap to this intake, you would probably want to retune your ignition curve and carburetor jets / rods; however, it wouldn't be necessary.
Thanks, yes I know you cant install an EGR valve on the RPM. I was more curious why they say its not "recommended" to use an EGR Qjet if one could just delete the EGR valve.
#6
Performer RPM doesn't have EGR provisions.
QJets that came on EGR cars are calibrated with an exceptionally lean part throttle to account for the EGR.
Ergo, putting an unmodified QJet from an EGR car onto a Performer RPM leads to bad times.
As with anything, the carb needs to be tuned to the new build. You can use later carbs, they may just need a bit more work than earlier carbs to run well.
QJets that came on EGR cars are calibrated with an exceptionally lean part throttle to account for the EGR.
Ergo, putting an unmodified QJet from an EGR car onto a Performer RPM leads to bad times.
As with anything, the carb needs to be tuned to the new build. You can use later carbs, they may just need a bit more work than earlier carbs to run well.
#7
The only things I can think of that might be different for a Qjet on a car with EGR is 1) the added timed vacuum port to operate the EGR valve and 2) the fact that the primary metering rods are likely to be lean at part throttle.
Neither of these is much of an issue. You can cap the port if you don't have EGR and you can change the metering rods (as you SHOULD anyway to match the flow characteristics of the new intake). Sounds like more uninformed BS to me.
#8
Performer RPM doesn't have EGR provisions.
QJets that came on EGR cars are calibrated with an exceptionally lean part throttle to account for the EGR.
Ergo, putting an unmodified QJet from an EGR car onto a Performer RPM leads to bad times.
As with anything, the carb needs to be tuned to the new build. You can use later carbs, they may just need a bit more work than earlier carbs to run well.
QJets that came on EGR cars are calibrated with an exceptionally lean part throttle to account for the EGR.
Ergo, putting an unmodified QJet from an EGR car onto a Performer RPM leads to bad times.
As with anything, the carb needs to be tuned to the new build. You can use later carbs, they may just need a bit more work than earlier carbs to run well.
Thanks that what I assumed. Edelbrock is alluding to stock EGR Qjets but they can be retuned to work with non-EGR intakes.
#9
What, exactly, is an "EGR-style" Qjet?
The only things I can think of that might be different for a Qjet on a car with EGR is 1) the added timed vacuum port to operate the EGR valve and 2) the fact that the primary metering rods are likely to be lean at part throttle.
Neither of these is much of an issue. You can cap the port if you don't have EGR and you can change the metering rods (as you SHOULD anyway to match the flow characteristics of the new intake). Sounds like more uninformed BS to me.
The only things I can think of that might be different for a Qjet on a car with EGR is 1) the added timed vacuum port to operate the EGR valve and 2) the fact that the primary metering rods are likely to be lean at part throttle.
Neither of these is much of an issue. You can cap the port if you don't have EGR and you can change the metering rods (as you SHOULD anyway to match the flow characteristics of the new intake). Sounds like more uninformed BS to me.
This is exactly what threw me off. Here is the pic notice the asterisk.
#10
It is just a disclaimer from Edelbrock so you do not remove or disable 73 and up factory emissions and the lack of the exhaust heat riser plate for the heated tubes to operate the choke. Any Quadrajet would need proper performance tuning to be optimal. Electric chokes are an easy retrofit too.
Last edited by GEARMAN69; January 11th, 2017 at 08:20 AM.
#11
They are just trying to convince people to buy their terrible Performer 750 cfm carb. Isn't that the worst one of the bunch? I have an EGR QJet on my Performer, tuned like Joe described.
#13
While we're on the subject of Eldebrock RPM intakes, what fuel line are you guys running from the pump to the carb? Stock 350-4bbl, 455-4bbl, one piece, or a 2-piece line w/filter midway? Pretty sure the intake is a bit taller then the OEM one and trying to put together another order for my build.
thanks,
Doug
thanks,
Doug
Last edited by derone; January 11th, 2017 at 10:34 AM.
#14
While we're on the subject of Eldebrock RPM intakes, what fuel line are you guys running from the pump to the carb? Stock 350-4bbl, 455-4bbl, once piece, or a 2-piece line w/filter midway? Pretty sure the intake is a bit taller then the OEM one and trying to put together another order for my build.
thanks,
Doug
thanks,
Doug
If you want a one piece line with flared ends you will have to make your own. I make my own with 3/8 aluminum line works well. I prefer the filter elsewhere for cleaner look. Fram paper in Qjet inlet minus the check valve crap or inline filter before pump
#15
Suppose I could do that. I'm really wondering if the 455-4bbl line would work on the 350ci, due to the slightly larger dimensions of the 455ci, when using the 350ci RPM intake, and hoping that the line might be slightly longer to compensate. Using a q-jet of course.
#16
Interesting thought. With stock intakes, the BBO carb sits 1" higher than it does on an SBO, thus that's the difference in fuel line length. I don't know if the RPM carb flange is that much taller than stock on a 350 or not, but you MIGHT be close enough to finesse the line into place.
#18
While we're on the subject of Eldebrock RPM intakes, what fuel line are you guys running from the pump to the carb? Stock 350-4bbl, 455-4bbl, one piece, or a 2-piece line w/filter midway? Pretty sure the intake is a bit taller then the OEM one and trying to put together another order for my build.
thanks,
Doug
thanks,
Doug
https://www.summitracing.com/parts/edl-8131
for the carb line to the pump i used is summit part number EDL-81233 , edelbrock braided fuel line kit for small block chevy. https://www.summitracing.com/parts/edl-81233
i had to shorten the line and use the following fitting
90 deg bend -6AN male to 5/8-18 inverted flare male
Part number EAR-AT949096ERL
https://www.summitracing.com/parts/ear-at949096erl
#19
you carb can easily be converted to electric choke. consider enlarging the idle tubes and idle down channel restriction if running a large camshaft, maybe increase the idle bypass air also. good luck
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