The Dodge Challenger Message Board

I've just finished installing an Innovate wide band air fuel ratio meter and I thought I ought to post the results so I and others who havent tried one yet can learn from it
Ok so drove in this mornin and tried all sorts of heavy engine loads in all gears and different eons, the idle is still pretty good at around 14, high vac part throttle gives over 15, cruising at 70mph gives roughly late 13's , so far so good but when I step on it I see no real change, maybe low 13's, too lean to make real power, I ought to be seeing low to mid 12's ideally.
So this evenin I will be mainly changing metering rods one stage rich, approx 4%, and secondarys two stages rich, approx 8%, idle mixture appears pretty good tho so I'll leave that, it's a piece of piss innit
_________________
Jesus built my hot rod

72 Challenger
65 Barracuda

Sounds like you have a handle on it Ade! Did you use the disc that Innovates supplies with their kit and plot the Air Fuel curve on a spreadsheet? I really like this feature although it's a bit outdated because it cant plot the engines speed just time. If I remember right it can plot up to 44 minutes running time? VERY IMPORTANT,,whats your timing curve with the vacum advance hooked up?? Do you use vacum advance? Yes, I would say the primary circuit needs a tad richening to around 14.0 maybe a tad richer than that,, 13.7 is where I'm at on cruise. You'll know when it's too lean by surging and if it's way too lean backfire. On the power side,(WOT), I'm at around 12.8 and it's very nice, pulls hard no hesiatation, very linear. Just a quick note, the highest vacum is achieved during de-cel when the throttle blades are nearly closed. Then it's idle followed by cruise. (My idle is 14.7),,My ground strap on the sparkplugs show a firing line at the radius,, just where Don wants it. The plugs are lightly tanned.(NGK-FR5 street plugs).

Yeah the vac is hooked up Edd, as per the old MP instructions, but the MP dist i installed last week doesnt work any where near as good as the FBO equipped std factory dist that was in there. I'll have to get the timing nice again and then start on the metering rod and jet changes....................I'm enjoyin this

Had a good day yesterday on this, got the MP dist dialled in nice, it was far too advanced, my initial has ended up back in the mid teens now tho so the FBO advance plate and springs will be goin in soon.
Went up one stage rich on the primary's and secondary's and got much better low speed driveability, that light throttle surging gone and much smoother in say 2nd or 3rd gear around town.
Still getting fairly high readings on the AFR gauge at heavier loads and WOT, still in the low 13's, still a lag when the secondary's are pushed open but it's much improved.
Going another stage rich to both ends today and see how it looks and feels, the Eddy will be 2 stages rich (8%) then, I'll keep goin till I stop feeling an improvement and then back up one stage.
That Innovate gauge is a massive help, the information you gather real time, real driving habits, 'kin brilliant

Finish getting your timing sorted out first mate. Then crack on with the carb.

The timing effects how well the fuel burns so also effects mixture readings from the exhaust.

dave-r wrote:Finish getting your timing sorted out first mate. Then crack on with the carb.

The timing effects how well the fuel burns so also effects mixture readings from the exhaust.

Ha........nice one Daveman, I second guessed that and modded the dist this afternoon
It's pissin down now so I'll do the jetting at work tomorrow, I made the mistake of going out before the weekend in the rain to read the AFR's at full load and span the car 180degrees , twat

Drive to work and back today and.............no difference in AFR's at WOT, but slightly better in part throttle and cruise, I think I must have weak fuel pressure..........actually I'm sure of it cos when I went to pull the fuel lines off to check it I only just realised I am still running the tired 40 year old factory mech pump and not the Carter street pump that I bought ages ago
I left the car with my lil nephew at his service station a couple of years back for an MOT and he was SUPPOSED to have fitted it then!!!
Better find all the goodies and get em installed, means that all my work so far has achieved very little tho ....... wot a cock

Make sure you use a regulator too mate.

Have you seen those new design of Holley and Edelbrock pumps that have a built in regulator adjustable from 6-8psi ? If I can't find that Carter pump, which is fairly likely , then I might go for one of these

I think you only want 5.5psi max for one of those Edelbrocks? Otherwise they flood.

Tested the fuel pressure at idle and up to a bout 2-3000 rpm without any load and I got a steady 6 psi reading on my gauge after the filter. That seems pretty good I think
I also modded my MP dist back to FBO spec, drives just loads better on light and part throttle, cruise etc but still seems too weak on the WOT test, AFR's reading low to mid 13's are all I can see.
Knowing the fuel pressure is pretty much there I'll just keep going up one stage at a time till I see an improvement. I can defiantly feel the motor holding back as it pulls up to max rpms and it still suffers a slight lag when the secondaries are pushed open, even gradually.

Adrian Worman wrote:Tested the fuel pressure at idle and up to a bout 2-3000 rpm without any load and I got a steady 6 psi reading on my gauge after the filter. That seems pretty good I think

Which pump were you using?

That was the stock pump Jon.