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9375 HP Dominator 3 circuit carb for single 4 app.

General engine tech -- Drag Racing to Circle Track

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ProGSX
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9375 HP Dominator 3 circuit carb for single 4 app.

Post by ProGSX »

Can someone tell me where a good place to start with the air bleeds for a single carb application? I have the same question for a 9377 HP also. The engine is a heavily modded Buick 455. Thanks
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Post by jmarkaudio »

Mark Whitener
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Post by ProGSX »

Mark,
Thanks for the reply, looks like I have alot of work to do. I was told the 9375 HP was a good choice because it did not have the over rich midrange like the 8896?
Jeff
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Post by andyf »

Start with the carb box stock and go from there. Many engine builders on this forum run the 9375 as their dyno carb. Do a search on "9375" and I'm sure you'll find a bunch of info.
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Post by Rick360 »

andyf wrote:Start with the carb box stock and go from there. Many engine builders on this forum run the 9375 as their dyno carb. Do a search on "9375" and I'm sure you'll find a bunch of info.
I've also seen 9375's work very well in stock form on single carb small blocks.

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Post by jmarkaudio »

If it is a non-HP 9375, it usually runs fine with the correct jets. I have one that came with no intermediate bleed inserts and works well as is with 92 jets and no PV's. There were metering changes on the HP versions, I am not sure about the main well size differences, but the e-hole size and number of holes are different. You can try the .025 MAB's and remove the intermediates, this is what is in the non-HP carbs, just watch your plugs. Different engines will pull fuel through it a little different, you may be fine with just those changes.
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Post by ProGSX »

jmarkaudio wrote:If it is a non-HP 9375, it usually runs fine with the correct jets. I have one that came with no intermediate bleed inserts and works well as is with 92 jets and no PV's. There were metering changes on the HP versions, I am not sure about the main well size differences, but the e-hole size and number of holes are different. You can try the .025 MAB's and remove the intermediates, this is what is in the non-HP carbs, just watch your plugs. Different engines will pull fuel through it a little different, you may be fine with just those changes.
Mark,
It is an HP, any suggestions on it?
Jeff
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Re: 9375 HP Dominator 3 circuit carb for single 4 app.

Post by andyf »

ProGSX wrote:Can someone tell me where a good place to start with the air bleeds for a single carb application? I have the same question for a 9377 HP also. The engine is a heavily modded Buick 455. Thanks
Have you run the engine yet with this carb on there? It might work just fine as is if you haven't messed with the carb yet. Do you have a wide band setup in the exhaust system? If not, can you get the car on a chassis dyno that is equipped with a wide band?
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Post by jmarkaudio »

Start with the changes I suggested, .025 main air bleeds and take out the intermediates. Same on the HP 9377. This will lean it a little at part throttle and start the mains a little earlier. If they still have issues, then look at the changes in the other posts. T-slots/idle circuit are part of the issue and may also need addressing. Jet 92 to 93 on the 1050, 94 to 95 on the 1150 without power valves as a starting point. Is this a street driven car or drag only? A wide band system like the Innovate is a good addition if you can swing it.
I have a 1250 that I converted to 2-circuit on my SB2 that works great, I started to convert my HP 8896 but wanted a larger carb and used the Demon blocks I had on the 1250. I have a pair of non-HP 9377's I am working on now, converted one with Quickfuel blocks and will run the other as is to compare. Hopefully get an A-B-A-B test.
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Re: 9375 HP Dominator 3 circuit carb for single 4 app.

Post by ProGSX »

andyf wrote:
ProGSX wrote:Can someone tell me where a good place to start with the air bleeds for a single carb application? I have the same question for a 9377 HP also. The engine is a heavily modded Buick 455. Thanks
Have you run the engine yet with this carb on there? It might work just fine as is if you haven't messed with the carb yet. Do you have a wide band setup in the exhaust system? If not, can you get the car on a chassis dyno that is equipped with a wide band?

Yes, the engine has about 45 minutes run time on it, drag only, no exhaust. Idle setting has been giving me trouble. Just when I think it is set the engine will fade and stall. I haven't done any dynoing with it.
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Post by ProGSX »

A wide band system like the Innovate is a good addition if you can swing it.
I think this is in order too. It is drag only.
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Post by andyf »

Sounds like the first place to start is the idle circuit. If your metering blocks are drilled for idle jets then it is just a simple matter of getting in there and changing the jets. Or you can see if you can fix the idle issue by just changing the idle air bleeds.

The problem you have is that if you don't have some sort of feedback loop then you really don't know which way to go. So you need to figure out if the engine is lean or rich before you start trying to tune it. Of course you can just guess and make a change and then see if it gets better or worse.

If your metering blocks aren't drilled for jets on the intermediate and idle circuits then one option is to pick up some new metering blocks that are drilled. The guys at BLP sell these "ultraHP" style metering blocks that are fully adjustable.
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joel fredericks

9375

Post by joel fredericks »

ive had one on and off my chevelle for 12 years now. they dont like to idle a real lot at least in stock form, with a warm spark plug it wasnt too bad, cold nos plugs sucked though! my buddy had his redone by jet about five years ago and its a really good mannered street carb now though he hasnt raced it since, at least at the track.

joel
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Post by Robbie DeVane »

if you dont have billett metering blocks I can convert yours to be totaly adjustable and cailbrate them to your combo. that will save you a couple of bucks, there is a pic of one done on my we sight just go to the catalog and go down until you see them. www.devanecarbs.com
DeVane carburetors are precision assembled and calibrated to YOUR combo. Are you ready for the next level of performance?
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