jspeeddemon

Jack, the jetting on my boat with M-4 and dual carbs is the same setup as yours except I had to take out the power valves, because they were staying open all the time. Now when Nickerson fixes the carbs for a blow thru, he stated to my buddy who has the twin, he references the power valves to boost instead of vacuum. He has not tested yet, still wainting on exhaust. I'll let you know. From the numbers I would guess SAM is jetting with a single carb. Also remember I talked to the guy that had a 622 M-4 and he ended up with 68 and 84 with power valves, but his carbs had been worked by Nickerson. Yank the power valves, test it on the ramp like I suggested and do a plug reading, I'm sure you'll find it's close. Also remember that if the power valve does not pick up the coprrec t signal it will open or close at the wrong RPM, than when you want it which is top end. It may stay open all of the time or closed all of the time, because of that variable you don't know, so to solve, temporarily remove it from the equation and jet from there. With two 540's running up here very similar jetting, I feel you are not going to burn it up if you are careful, starting from where we are at. Altitude will be the biggest difference in the packages, otherewise they are very close. If you do the ramp test and the motor runs smooth you are not likely to let your emotions run away and nail it before reading the plugs again, I know from personal experience. It's hard to resist the temptation when that motor feels so smooth. Good luck Jack.

Turbojack

OK guys & gals I know we are OT.

Jspeeddemon
Thanks for the info. I did a search on OSO on carbs & jetting & I can not sleep thinking about this. I guess it it better than not sleeping worring about work.

Sec Agent Man

U.T. we should be arriving on Thursday sometime with our S.A.M. 25 Eliminator. We would be more than happy to have you guide us. We are most excited about this trip, talk about not being able to sleep. Thanks for the altitude info, very helpful.

Jspeeddemon, we have twin Nickerson carbs on our engine application.

Turbojack, we have a 540 with... ok, I can't tell you everything or my wife will take the boat away from me.

TBS, break the code. (If you can figure it out I have to speak in code, she's watching, perhaps she won't know what TBS means.)

Should I be packing more jets? Or do I need more boost?

Uncle Toys

STONE – I received my garage art yesterday (your post 3/22/02). That was exceptionally nice of you, especially the display case thing - THANKS! It will be on the garage wall next to my glory-day’s pictures in time for the regatta. By the way, how is your boat coming? Are you going to make the regatta? Haven’t seen you on the board for a while.

Turbojack

elmi

Have you tested yet? I am still trying to get jetting correct. Getting close, hopefully this weekend can get some big numbers.


Jspeeddemon

Has your friend gone out yet with his new redone carbs?

jspeeddemon

He is still waiting on the headers for his boat, supposed to be here today. I will email as soon as i know, I read your post to tomcat, and I assume that you got to ride with some success. Those black plugs are tough to deal with, if you leave power valves in and try jetting down on jet sizes, you will find your power. Certainly if your plugs are black, you don't have to worry about tool lean at this point, just make short bursts of WOT till the plugs clean up. You can't check the plugs too often, till you get the setup correct. The plugs should maximum of tan at WOT, no black whatsoever, it would be nice if you had pyrometers. I can see about a second set of plates for yours, the pyrometer probes and meter is about 300 hundred from Jeg's.

Turbojack

My problem is I am to hard headed. I hear & read what you & everyone says but still have to try it myself. Last trip out last sunday in taking off if I got to far in secondarys motor would fall on face. Once planed off running at 2100 & nailing it the motor would rap to 4K, then start falling off. After backing out it would take a while for motor to clear up. Last trip out was 70 primary, 8.5 PV, & 85 secondary. I rejetted last night down to 83 in secondarys for next try out this saturday. Boat ran with 72 in primary but when I had 74's could not even get it to run. As I posted earlier I am going to take pressure reading in box at all of the RPMS so I will be able to see when power valves are opening. I finally snaped last Sunday that I only need to install 1 new plug each time I do jet change. At least until I start getting close. I am a long way from where procharger said to start & still not there.

Turbojack

jspeeddemon

On plates, are you talking about putting spacer between head & header & putting probes in this spacer? What does that do to the exhaust out the back??? If cost is only $300 for this & you can keep better eye on engine it is cheap insurance compared to tearing up another motor. I rather spend my money on either EFi or something else that to pay to have engine rebuilt from melting down another one. ( Yes, over the last 25 years I have melted down a motor or ????)

Cattitude

Good luck on your tuning- I hate to say it, but boy i like my efi.

Dustin's kit uses a pyro that taps into the manifold at #1 I think. I bet he could set you up with a probe and gage to go with it. I'd rather do that than introduce another gasket to my exhaust system and stretch the plumbing to make up a 1/2".

Again, good luck sorting out the jets!

Turbojack

Cattitude
I have the CMI elbow tops. Will this probe go in this header. There is aprox. 3/7-1" before the pipe is sleaved.

Before I knew that this board existed I was looking at either whipple or procharger. I wanted package to fit under my motor cover & only had 2 choices Whipple quad with EFI or Procharger stage 4 with twin carb. I had called whipple & was given a price in the neighborhood of $14K for the quad rotor, intercooler, & manifold. I was also told I was on my own on getting the EFI to work since they did not want any part of it. I had asked the person who to call but he said did not want to refer anyone.