Nostalgias
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Nice pictures and write up Guy. Good to see things moving in the right direction. I'd hold off the transbrake for a bit, I think you need to mess with the carbs first. I think what you have is a lean bog, don't forget you have no power valves in a centre squirter to help you out when you mash the throttle, the accelerator circuit is the only instant enrichment you have and it's only one pump and in effect, only one squirter to do it with. I don't know what main jets you have in the carbs, obviously you need to square jet. Think I had 74's when I ran a 383 with a tunnel ram, so you'd need more jet than that, perhaps it's already a bit lean at idle? It's probably why most centre squirters have been modified to delay the secondaries opening and keep the air speed up and stop it going lean. Big pump cam and bigger squirters (Assuming they're available) is what I'd be trying first.
I have jetted both carbs square with 76 and it maybe be a tad rich while at WOT as I am getting an AFR of 11.9 at idle I have an AFR of 13.5. You are right it is a lean bog as the AFR momentary jumps down to 22 when the pedal is mashed. From what I have found the #25 shooters are all thats available for the centre squirters I can fin no record of any larger shooters anywhere on the WWW even those fitted to the 850CS were only 25's unless of course someone know's different. I have even looked into the possibility of drilling the rear of the carb body and fitting a second pump shot with a different metering plate to double the amount of fuel available to the shooters. I have two pump shot cam kits and the ones fitted to the carbs were bigger than any found in the kits. It was suggested that I leave the arms loose so that the shot hits later I already have the cams mounted in hole 2 on the throttle arm. I suppose I could always make a couple of cams that hit later..
Anyhow i must go off to bed now, its been a long night at work still only one day left then another four off
Anyhow i must go off to bed now, its been a long night at work still only one day left then another four off
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mopar_mark
- Posts: 6738
- Joined: Fri Jul 14, 06 8:01 pm
- Location: Windlesham, Surrey
Blue wrote:Guy, there's a Dominator pump cam that I don't think you get in the selction pack, shifts an insane amount of fuel, Pete know's it, yellow? Try that and possibly drill the shooters, sounds like you need a lot of fuel in quick as possible to make up for that initial huge gulp of air.
Pete wrote:Yes, Yellow and Dommie specific. Doubt they would fit a 4150.
The 50cc conversion bits for a 4150 may suffice.........
Blue wrote:Centre squirters already have a 50cc pump, which is why I'm saying an agressive cam to really work it.
Pete wrote:I remain to be convinced that one 50cc pump is enough in radical engines.....
If only we had more posts of this kind, what a great site this would be
"I spent a lot of money on booze, birds and fast cars. The rest I just squandered."
Many thanks for the imput guys
I am open to any suggestions the more the better
Blue wrote:Guy, there's a Dominator pump cam that I don't think you get in the selction pack, shifts an insane amount of fuel, Pete know's it, yellow? Try that and possibly drill the shooters, sounds like you need a lot of fuel in quick as possible to make up for that initial huge gulp of air.
I am already running these ones http://www.summitracing.com/parts/hly-20-81/overview/ they do list another set of cams for the Dommie but they look like they are more gentle than thesePete wrote:Yes, Yellow and Dommie specific. Doubt they would fit a 4150.
Blue wrote:Centre squirters already have a 50cc pump, which is why I'm saying an agressive cam to really work it.
Pete wrote:I remain to be convinced that one 50cc pump is enough in radical engines.....
Although this does look like it may come with some issues ie how to mount pump shot lever and cam. I am already using the rear bowls off a double pumperGuy wrote: I have even looked into the possibility of drilling the rear of the carb body and fitting a second pump shot with a different metering plates to double the amount of fuel available to the shooters
I am open to any suggestions the more the better
Guy, looks like you already have the cams I was thinking of, so how about drilling the shooters to get some of that volume in real quick? I would think that fitting a rear pump and metering block probably wouldn't be that hard, but you'd still have the restriction of a single shooter feed, not sure it would achieve the desired result.
