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 New 2 Circuit 8896 Dominator Conversion 
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Sat Jun 10, 2017 11:08 pm
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STEFF wrote:
Had an interesting learning experience today. I have an Aero hood scoop on my car that is seperate from the hood. All the tuning I've been doing had been without the hood or scoop on. Less hassle making quick changes. So, I decide to drive it to work this morning. I throw the scoop on and the hood and go on my way. I notice this thing is running a bit leaner. Everything went in AFR about 1.5 to 2 points leaner across the board. So, I took the scoop off and everything went back to normal. Naively, I never expected that to happen that much as the scoop is not sealed to the carb. So that thing is stuffing that much more air in the carb or ?? Attached is a pic of the scoop. And to be honest, I'm not super crazy about the scoop. I wanted to experiment with carb spacers as the car reacted well to past plenum volume increases and wanted to find the max. To compensate for the scoop, should I throw jet at it or ??



Test the way you race or you have no f-ing clue how it's going to act...........learned that years ago........flute, maybe maybe not just have to see what happens............Next guy that tells me a WB is for people that cant tune is gettin slapped.......... ;)


Sun Jun 11, 2017 10:19 am
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Joined: Fri Jun 02, 2017 2:54 pm
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Yeah, I totally missed it on not thinking how much influece the scoop was going to make. I just made a flute to work with the carb stud. I'll see if it makes a difference shortly. I've always used one for the track, but it was intended to prevent fuel slosh during lauch, when the wheels come up. The wide band is a blessing and a curse. Its great to see what changes make to the curve but then it makes start to obsess over the stupid numbers versus seat of the pants.


Sun Jun 11, 2017 2:15 pm
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Joined: Fri Jun 02, 2017 2:54 pm
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I got the car out for a ride with the flute added. With same 64/28 bleeds, same 86/94 jets, 2000 to 2500 it was in the, 16-17 range light load. 3000 rpm afr's got more normal 13.0-14.0 incline load. 3500 13.1-14.2, 4000 rpm incline load 13.0-13.8. Nutting it from 3500ish to 6500, dropped to 12.1 then leaned out to 12.7 as rpms increased to 6500

My cruise sweet spot is 2800-3500 ish rpms for most driving. 3500 is 55mph, 2800 is about 45mph ish. So, I think most of the cruise rpm in that area are on the main circuit. I could be wrong but It just feels like it.

One thing that is very prevelant is, anywhere in the cruise range even above 3500, when transitioning from a load from an incline to level or down hill, no load situation, the motor gets quite bitchy and the AFR goes lean into the 15-16 range, and you can feel it surging back n forth. Get into it and it goes away.

So, after seeing the low rpm lean, I reduced the IAB to .061. It helped a little to bring the 2000-2500 AFR down into the 15 range, but it still seemed lean by the engine sound and fattened up the light load acceleration from off idle getting up to speed. So I thought maybe richening up the transfer slot jet would richen up that 2000-2500ish range. I increased it from .055 to .058. and got out for a quick spin. Didnt seem to do much but just ran out of time.

This scoop seems to be playing hell with the low rpm range and no load cruise. So, do I keep reducing the IAB untill the AFR comes down? Is increasing the Transfer Slot jet the right direction for fattening up the idle circuit cruise rpm range (2000-2800)?

How do I fix the no load cruise lean situation?


Sun Jun 11, 2017 10:49 pm
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As often as not that level road steady speed no load and slight down hill burble is from too rich, not too lean. The too rich burble tricks the WBO2 to read lean because of the unburned O2. Any misfire makes a lean reading, rich, lean or ignition related.

To rule out that possibility drop the T-slot jet to .052" and play the IAB some after, to see what happens. Sorry if this sends you on a wild goose chase.


Sun Jun 11, 2017 11:29 pm
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Joined: Fri Jun 02, 2017 2:54 pm
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tuner wrote:
As often as not that level road steady speed no load and slight down hill burble is from too rich, not too lean. The too rich burble tricks the WBO2 to read lean because of the unburned O2. Any misfire makes a lean reading, rich, lean or ignition related.

To rule out that possibility drop the T-slot jet to .052" and play the IAB some after, to see what happens. Sorry if this sends you on a wild goose chase.


I will give that a try, but it's not the burbling you get when you got your foot in it, then take your foot completely off the pedal and hear that burbling going on from unburned fuel and a closed throttle as it is deceling. This is with the throttle still open and just letting off slightly to maintain a specific rpm/speed. You definitely feel the car surge back n forth like its lean.

It just sucks, because the car runs really good without the scoop and the air cleaner in the wide open air.


Mon Jun 12, 2017 6:55 am
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