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twase |
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I have a GRA Carb that has not been tuned, I want to know what size Progression jet people are using on there I6, NA motors. Mine was 2.5 mm and I drilled it out to 3mm, while its better I still have sluggish performance off idle but idle is OK and WOT performance is great. If it was a carby it feels like a flat spot that recovers after around 2000rpm.
_________________ BF Fairmont Ghia Series II update. |
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aaron_hogan |
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i would have retained the stock size progression jest and instead taken a look at the metering rod. Especially if you bought it second hand as they are always different. I'd have to pull my fuel hose off to check but i can do that to tell you what metering rod i have.
The other thing i guess is ensuring that you are not over-carbed in the first place. What cfm is it? 400 or 440 or higher? 400 is spot on for 4.0 in my experience and i've had it on a few diff engines as the car evolved.
_________________ EA SVO Fairmont Ghia - Recaros, Bilsteins, Sunroof, SVO rims and body kit, Genie headers, DBA rotors. T5 steeda triax short shifter. 3.27 lsd. (EL 4.0 ported/polished, rebuilt and balanced, Dev5 cam. J3 chipped EL ecu, AU injectors). |
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twase |
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aaron_hogan wrote: i would have retained the stock size progression jest and instead taken a look at the metering rod. Especially if you bought it second hand as they are always different. I'd have to pull my fuel hose off to check but i can do that to tell you what metering rod i have. It is a 480 but was told this is OK. It would be great if I could get the jet size so I can get that out of the equation.
The other thing i guess is ensuring that you are not over-carbed in the first place. What cfm is it? 400 or 440 or higher? 400 is spot on for 4.0 in my experience and i've had it on a few diff engines as the car evolved.
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aaron_hogan |
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nup mate its too big. no wonder it feels sluggish. Your mixtures are too rich and you can't tune that out. Send the carb back to GRA to go down in cfm OR find somebody to swap with. Pity that my mate already paid to go the other way (400 re-worked to 480). I have a 400 and a 440 here but they are kinda pegged for a job. On my V8 i have a 400 and a 440 and it isn't tuned yet. Once i know where i stand with the tune on it, and figure out if i need to step up to 440 and 480 i might be up for a trade.
There are plenty of them out there finding one isn't hard but the prices seem a bit silly to me at the moment. +$400 second hand is just silly. I remember buying them for $150 at swap meets and out of the trading post not so long ago.
_________________ EA SVO Fairmont Ghia - Recaros, Bilsteins, Sunroof, SVO rims and body kit, Genie headers, DBA rotors. T5 steeda triax short shifter. 3.27 lsd. (EL 4.0 ported/polished, rebuilt and balanced, Dev5 cam. J3 chipped EL ecu, AU injectors). |
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twase |
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Thanks for the info, what price for the rework if you know?
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gogetta |
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i contacted gra and they said a 350 is good for stock motor and 400 for a worked motor - 4.0lt I6 that is
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twase |
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gogetta wrote: i contacted gra and they said a 350 is good for stock motor and 400 for a worked motor - 4.0lt I6 that is Thanks for that, I can live with the performance but it is cause for concern at intersections if it stumbles. I might go back to the original setup till I can get another carb. Anyone got a 400CFM for sale or swap?
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