I've looked around the forums and I haven't been able to nail down wither or not a 48 is usable on a stockport 12a. I read JEEZUS' thread on it but it lead to a dead end as he didn't end up running the 48. I've seen some mumblings that a 48 is in fact great for a stockport but I haven't been able to find a definitive answer or a setup that includes the E tubes, jets and all that. Racing Beat says the Weber 48 is NOT good for stock ports. Can someone enlighten me?

 

You can use it on a stock port but you should have a fully tuned exhaust and a stronger ignition than stock to take advantage of it. Even with OEM engines each one is a little different so no one tune fits all. I don't have any specific tune to offer, I ran a Dellorto DHLA 48 from RB for years on my stock port. The down draft can't be that much different I would think.

 

48IDA is flexible enough to work with a stock port engine, but for a stock port engine, the nikki is a really good choice, especially on the street.

you won't find a good jetting chart, and if you do, you don't know what AFRs they picked, what fuel pressure they ran or even how well it ran (if at all) plus the exhaust matters.

in general you'd want venturi's that were 38-40mm, F7 E tube (the F11 is for VW's), idle jet is going to be 50-65, main depends, but 150-180 and air should start about 30 less than the main fuel jet. with an oxygen sensor you'd be looking for AFR's around 12.2-12.5 at idle, 13.5-14.5 at cruise, and WOT should be 12.5-13.2.

 

Would you say any rotary engine should be running at those afr's? Or just 12a?

 

You can use a 48 ida in any rotary engine as long as u jet it correctly. I would use 37mm chokes f11 or f2 emulsion tubes 160 to 180 main jets, 60 idle jets 120 air correctors and a 3mm needle and seat. ,This set up will run well on a stock port 12a

 

Which E tube is better for the street? F11 or F2?

 

pretty much any non turbo engine will be in that area. turbo wants to be richer in boost, because its using the richer mixture to control detonation and keep temperatures in a place that doesn't melt the turbo.

with an NA detonation and EGT's aren't a worry unless you're going racing or something that will be WOT all the time, then you will want to be on the slightly rich side.

for an example, my friends and i have done a few 25 hour long races, with a honda, and when you have the gas pedal floored for a day, 13.3:1 AFR is too lean, and it blows up. if you have it on the street at 13.3:1 its ok, because it does not see full throttle long enough to get hot enough to start detonating and blow up. rotary is no different, just more forgiving

 

That's why automakers and the more recent standalones will do power enrichment based off of time at WOT. You don't need enrichment at all for the first few seconds.

Supposedly the new Ford 7.3 gasoline engine for the medium duty trucks never needs to go into power enrichment at all - stoich at WOT up to redline. I'd like to see what they plan on using for catalysts.

 

Either will do there is very little difference . I prefer the f2 though

 

i've done some testing with the S4 and S5's and a little with the FD, and with the S5 they had to warranty the cat, and it runs much richer at WOT than the S4 does.

i've also heard that the newer Ford ECU's (among maybe others) is actively looking for MBT, and will correct for fuel quality.

 

f-3 are just like the f-11 same holes exactly ..f-3 has a deeper well inside the tube that makes it better for our engines ......f-7 are good to ..i just used those for turbo applications