QFT SL-600-VS Tuning

Re: QFT SL-600-VS Tuning

Postby Nick_nl » Tue Aug 09, 2022 8:37 pm

Well, my first idea would be if it runs fine, don't change anything.
Just use a good fuel filter and keep the carb clean. :)
Are you running the front primary side without a power valve? I would use one, it helps with fuel mileage.
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Re: QFT SL-600-VS Tuning

Postby JedIEG » Mon Oct 17, 2022 4:45 am

I do run a power valve. Next step in WOT tuning is to take some main jet out and reduce the PVR... 10:1 is a way too rich.

Well I'm still not happy with the carb. Transition still sucks and I messed with the IFR and got my cruise all screwed up... time to reverse that and try something else... . It seems most people blame the oversized transfer slots in the modern QFT baseplates for idle and transition issues, so I am considering swapping it out for the baseplate off the spare 80457 I have on the shelf or buying a list 6160 plate (oe for a '72 mopar) off Ebay and clean it up. Any pitfalls with that or better options?
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Re: QFT SL-600-VS Tuning

Postby Nick_nl » Mon Oct 17, 2022 8:36 pm

You could also use Transfer Slot Restrictions in the main body. 10-32 0.081" hole. This way you can change the part throttle fuel flow. WOT should be boosters and powervalve.
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Re: QFT SL-600-VS Tuning

Postby JedIEG » Sat Nov 12, 2022 6:47 pm

So I have been beating my head against a wall trying to figure out this carb. I found a thread from the old forum that describes calibrating a HR-580-VS which is basically a 4150 version of the SL-600-VS. So I tried to get my calibration close to that using my original metering block in the rear and the billet one on the front. It runs like crap. I know the cal is not exactly the same as suggested in the old thread but I would expect it to be better. Am I missing something critical here?

Old thread:
https://www.tapatalk.com/groups/racingfuelsystems/going-through-a-qft-hr-580-vs-or-mish-mash-with-sl-t2028.html

My Baseline and new cals:

SL-600-VS Cal.JPG
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Re: QFT SL-600-VS Tuning

Postby bigblockmark » Sat Nov 12, 2022 11:24 pm

Those carbs are what keeps Edelbrock selling 60 year old design Carter AFB and AVS
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Re: QFT SL-600-VS Tuning

Postby rgalajda » Mon Nov 14, 2022 12:13 pm

Here are some findings that I recorded working on a 580 VS Brawler / Quick Fuel ( I am fairly certain this was as original ) No issues had been reported.
4 corner idle
MJ #66
SJ #70

Primary metering block
PVRC ( I din't measure this )
IFR .032" up high
E .027
E .032
E .032

Secondary metering block
IFR .032" up high
E .027
E .032
E .032

Main Body primary
IAB .073"
HSB .031"
Secondary
IAB .073"
HSB .031"
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Re: QFT SL-600-VS Tuning

Postby rgalajda » Mon Nov 14, 2022 12:25 pm

I should have noted the reason the 580 vs was removed ,was because I restored the original carb for the car. He had been driving the car for 2 years with the 580vs. It was on a 1968 302 Cougar , all original.
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