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11-05-2012, 07:22 PM | #1 |
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Tired of TBI issues, what size carb???
I have a 1987 one ton, with a 454 turbo 400, mild RV/ towing cam with TBI problems, and I'm tired of throwing money at it! So I'm going with a carb and intake set up and a fuel regulator to use the stock electric pumps. I'm going to be using the weiand 8017 manifold but need to know what size carb I should use, I have a 585 CFM Holley from my 327CI but I'm thinking im going to need at least a 650, any suggestions??
It will also have a MSD dist. and box, and a set of small dia primary headers. |
11-05-2012, 09:58 PM | #2 |
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Re: Tired of TBI issues, what size carb???
i have a stock 95 454 with the peanut port heads going in my 86 soon. i have done a lot of reseach with what carb to use and came up with the street demon 625. with your build being very simular, you just adding a mild cam, a 600 to 650 should work well
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11-05-2012, 10:59 PM | #3 |
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Re: Tired of TBI issues, what size carb???
Buy a quadrajet. They work great on 454 powered trucks. Small primaries for economy and big ass secondaries for passing.
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11-05-2012, 11:27 PM | #4 | |
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Re: Tired of TBI issues, what size carb???
Quote:
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11-05-2012, 11:40 PM | #5 | |
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Re: Tired of TBI issues, what size carb???
Quote:
For your towing I would recommend a vacuum secondary holley 600-650 Regulate to 6psi and a distributor that's not computer controlled. Posted via Mobile Device
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377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511 |
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11-06-2012, 03:26 AM | #6 |
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Re: Tired of TBI issues, what size carb???
Just my humble opinion, but my guess is you'll be a lot more tired of that carb in time. Sounds like you just need a new TBI unit from someone like Holley or something.
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11-06-2012, 07:26 AM | #7 |
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600 cfm is fine for a bb you could run a 750 but no real need to. either way your going to give the engine more air then a stock 2bbl tbi would. it still amuses me that it must have been a huge secret or some thing but ford 460's pre fuel injection ran 600 cfm carbs from the factory and man could they run.
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1976 Custom Deluxe SWB Med FMB.3/4 Drop. Gen VI 454, Muncie HD 3 speed With Modified OE Hurst Shifter, 3.73 12 bolt, GMPP HO roller cam, Hooker headers, Performer intake with modified Q-jet, Accel distributor. Best 1/4 12.3 @108. Funnest run 19.84 @88 full 1/4 mile burn out. 1997 K1500 ext cab 5.7 stock except muffler |
11-06-2012, 08:36 AM | #8 |
BAD BOW-Silverado XST
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Re: Tired of TBI issues, what size carb???
Most TBI operation problems are caused by poor fuel pressure.
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11-06-2012, 10:18 AM | #9 | |
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Re: Tired of TBI issues, what size carb???
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"The Ghost II" - 1987 V30 CC, 14-BFF (2nd Design Heavy Ribbed HD) SRW Conversion, 454/4L80E/205, 6" Springs, 35" Toyo MT's on 17" Classic II's, Full Audio System, Lot of Other Goodies!
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11-06-2012, 08:26 PM | #10 | |
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Re: Tired of TBI issues, what size carb???
Quote:
http://www.demoncarbs.com/1900.asp |
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11-06-2012, 08:39 PM | #11 |
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Re: Tired of TBI issues, what size carb???
(1) more vote for the quadrajet.
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1999 GMC Suburban K2500 SLT, 454/4L80E 1991 Z/28, 6.0L/T56 1949 GMC 250, S10 Frame, 6.0L/4L80E Instagram @aceshighspeedshop |
11-06-2012, 08:45 PM | #12 | |
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Re: Tired of TBI issues, what size carb???
Quote:
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11-06-2012, 09:14 PM | #13 |
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Re: Tired of TBI issues, what size carb???
with a good operating choke/carb, you shouldn't have any issues. the quadrajet on my old k10 would fire the engine even at -10*. what is "cold weather" to you?
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1999 GMC Suburban K2500 SLT, 454/4L80E 1991 Z/28, 6.0L/T56 1949 GMC 250, S10 Frame, 6.0L/4L80E Instagram @aceshighspeedshop |
11-06-2012, 09:20 PM | #14 |
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Re: Tired of TBI issues, what size carb???
http://www.summitracing.com/parts/DEM-1900/?rtype=10
Street Demon 625 EFI carb and it is budget friendly too. From the ads I have read it installs in 30 minutes and has one wire 4 bolts and no laptop or computer to tune it.
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11-06-2012, 09:32 PM | #15 |
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Re: Tired of TBI issues, what size carb???
Well im in texas so to me cold weather is around 10*, to about 35*. Typically that's what you see around here. But my quadrajet on my 82 (newly rebuilt) hated anything below about 30 so I guess anything below that temp I would consider "cold" when it comes to this. I've also had a couple other carb'd vehicles that were the same way. Though I no longer own any of them. Went with TBI lol. Seemed like every carb I've ever owned was just trouble waiting to happen if it wasn't already happening. That's why I always just recommend fuel injection cause it ditches the long list of problems that carbs eventually have. Just my personal experiences i guess.
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11-06-2012, 09:35 PM | #16 |
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Re: Tired of TBI issues, what size carb???
i rebuilt the carb on my pickup when the cam went flat at 88k miles, it was still going strong 10 years later when i sold it, and it didn't live an easy life.
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1999 GMC Suburban K2500 SLT, 454/4L80E 1991 Z/28, 6.0L/T56 1949 GMC 250, S10 Frame, 6.0L/4L80E Instagram @aceshighspeedshop |
11-07-2012, 08:20 AM | #17 |
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Re: Tired of TBI issues, what size carb???
Tear down an old carb'd engine, then do the same to a TBI or MPFI engine. Difference in cylinder wear will make you a TBI fan, quick. All the older blocks I tear down have a significant ridge at the top of the bore from wear...almost every TBI or MPFI engine I've torn down still has visible hone marks in the bores. A small part of this is due to lighter ring pressure against the cylinder walls, but the majority is the TBI. With a decently tuned TBI, you never get fuel wash down the cylinder walls, you never flood out, your engine is metered fuel as it needs it and it's monitored by the O2 sensor.
And you can get a TBI harness that will let you run a 4L80E tranny for around $300. That in itself would weigh heavily on my decision. I'm converting an '85 1-ton dually to TBI for just these reasons. |
11-07-2012, 08:28 AM | #18 |
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Re: Tired of TBI issues, what size carb???
I hope that I have figured out the problem, my Speedo is not working! So no Vss signal going to the ecu causing the lean stumble/ surge, I think it may be the gear in the trans. Man I hope this fixes it!
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11-07-2012, 09:27 AM | #19 |
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Re: Tired of TBI issues, what size carb???
sounds like your truck needs to go to a reputable shop and get fixed correctly.
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11-07-2012, 06:15 PM | #20 | |
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Re: Tired of TBI issues, what size carb???
Quote:
Flame suit on! LOL |
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11-07-2012, 06:48 PM | #21 |
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Re: Tired of TBI issues, what size carb???
Good news, the truck is running perfect now, the 90deg Speedo adapter was shot, hooked the Speedo cable directly to the trans, and all is good! I had no idea that these early trucks had the vss sensor in the Speedo itself. Glad I did not blow all the money on a carb set-up
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11-07-2012, 08:57 PM | #22 |
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Re: Tired of TBI issues, what size carb???
Man, I've lived in places that get to -40 and carbs was all we had. They started then.
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11-07-2012, 10:26 PM | #23 | |
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Re: Tired of TBI issues, what size carb???
Quote:
As for cold starts in carbs. Why is it that my holley with no choke horn and engine with lopey cam can start right up in 20*f weather in Washington and I haven't touched my carb since I first tuned it three years ago when I first installed the engine in July! Because i put some effort into understanding how a holley works and tuned it accordingly. So only expect as much gain from your carbs guys as you put into them. A tuned carb still kicks a computer in power all day Posted via Mobile Device
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377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511 |
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11-07-2012, 10:37 PM | #24 |
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Re: Tired of TBI issues, what size carb???
bigblocksrule, if an engine is having fuel wash issues(like you are describing), the carb is way out of tune, way too rich. you can get the same fuel wash with a fuel injected engine. i had a friend do a 5.3 swap into a g-body, cam, heads, headers, different injectors, etc. his mail order tune was rich and he washed the rings out.....with mpfi. it's all about the tune, just as insidious talked about.
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1999 GMC Suburban K2500 SLT, 454/4L80E 1991 Z/28, 6.0L/T56 1949 GMC 250, S10 Frame, 6.0L/4L80E Instagram @aceshighspeedshop |
11-07-2012, 11:23 PM | #25 |
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cool glad it was an easy fix 20 bucks compared to 500 is always nice in my book. as far as engine wear issues has nothing to do with induction its more of a modern materials used in newer engines and modern oil.
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1976 Custom Deluxe SWB Med FMB.3/4 Drop. Gen VI 454, Muncie HD 3 speed With Modified OE Hurst Shifter, 3.73 12 bolt, GMPP HO roller cam, Hooker headers, Performer intake with modified Q-jet, Accel distributor. Best 1/4 12.3 @108. Funnest run 19.84 @88 full 1/4 mile burn out. 1997 K1500 ext cab 5.7 stock except muffler |
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