OK, so I put the 2 needle carb on the Infiniti .18, sealed it, put the tiger drive and a better air cleaner on it...When I bench tested it I used the stock tank (I had taken the whole car apart to inspect while I was at it) and rigged up the S-Maxx's exhaust pipe to the stock manifold and it had run nice and smooth...didn't run it too long, as it was bench testing it, but powered through the power band and it had a smooth response and appeared to be decently tuned at a good temp...Then I finished reassembling my syclone and let her rip...she's extremely sluggish, getting hot, and won't tune decent (all the same problems as before)...I tear the whole thing down again thinking maybe I put something back together wrong...Well, Me being me, decided to tear down the pipe (stock one is 3 piece screw together) to see if I could come up with a better one, or modify stock baffles...When what to my wondering eyes should appear...A great big piece of flash (extra scrap plastic from manufacturing) sitting in the chamber between the baffle and the stinger tip and a lot of excess fuel/oil in the pipe (running extremely rich although running hot had been my problem)...It was blocking 2/3's of the stinger tip...I took it out, as well as took an X-acto and smoothed the flash from loose fitting details in the mold for the holes in the baffle...So...we talk about porting and polishing the engine and the exhaust manifold...but I've now learned that it should be done inside the stock exhaust pipe also...Will see if it runs any better when I get out of work tonight....Just wanted to let anyone having this tuning issue know what I found as ANOTHER possible cause....

Nice find on that, and thanks for sharing it, i have a friend have a problem with his. Im checking his muffler.

No problem Harry...I grew up building models and spent 8 yrs working in Injection Molding...I have had this basic problem, and seen a lot of other people complain about not being able get it tuned, and Although I'm not positive this is the problem, I've tried every other suggestion on this forum as well as the one's in the Engine forum and nothing has worked yet...I noticed the difference between running the two pipes, so that kind of narrowed it down what to look at...I'm also cheap with a lot of fabrication resources available to me, so I like to make all the hop up parts I can so I wanted to take it apart to study it's design anyhow...Will keep you posted when I try it out again, but 2/3's of your exhaust flow blocked up is a major problem...think of how a real car acts up with a blocked up Cat or Muffler...same symptoms...It could also be related to all the problems people are having with the fuel tanks since it would also be throwing too much back pressure in the tank thus causing more fuel into the engine along with excess back pressure working against the piston and our tuning it extra rich trying to get the temps down...Excessive front bearing leaks, carb o-rings going bad...all could be a result of excessive back pressure...Just a logical mechanical assumption based on known facts...it could just be a crock on my part, but it all makes sense to me since I found it....

It does to me as well, I to do some fabing in my shop for myself and my friends, so im no stranger to how this works. I would have thought that most of the problems parts wize would be taken care of in quality control. I am more anal about going over the RCs now than before. It just makes sence to check it once and then check it again.

In most factories, QR get's over shadowed by production...and in this case, I think QC would only be checking that the screws are tight and that it's not cracked after being put together...so Foreign debrie internally at assembly wouldn't surprise me and would be hard to get picked up by the QC dept...That and a lot of factories of non critical components only do sample inspecting...

Yea that makes sence. Im going to the HPI pipe myself no baffeling. They have special designs ribs for the air flow, its a little louder but much better.

yeah, I've seen that...I've been thinking of this design myself, but I'm still trying to find the theory behind all the designs...

If i find out, i will let you know.

Great info here guys [sm=thumbs_up.gif]

Thanks for taking the time to let us all know.

Mark

No problem TST...I try when I can...LOL...that's how we all get better, right...learning from other's mistakes and finds???

OK...so, it's running smoother, and a little better, but it's totally dogging...don't think I still have an air leak...Either I have a bad gear ratio when I switched to the 1 spd (17t clutchbell with whatever gear comes in the one speed tranny I bought...I think it's 44t), those MPI springs are grabbing way too early, or because the Infiniti engine doesnt have a pin in the block to line the piston sleeve up to (does have a notch), I have the timing off (but should be close)...or after how ever many tanks with too much back pressure, I lost the pinch in the engine or something like that...but it is just not building any RPM...It sounds more like a 4 stroke lugging around...after about 25 ft going down hill in my driveway, it started to pick up speed just in time to hit the brakes and turn around, which is why I'm thinking clutch springs...Any more suggestions???