Using Megajolt output to control a solenoid on the lean out pipe
Turbo Mini Forums

Howdy,

Just thinking out loud here, and want feedback or critique or 'good idea' 'bad idea' comments.

The Megajolt has outputs (v4 I am using) and I have a prob where its leaning out on boost.
I am thinking a solenoid controlled by the Megajolt output would work.
Under low load it opens the solenoid (therefore lean out pipe is normal) but as soon as the load increases to 90kpa or 100kpa it shuts triggers the solenoid to close.

Only issue is that if you nail it get on boost, shift gears (load drops) and the solenoid will try to open again, then you nail again it tries to close... maybe thats something I can control with the outputs - will look into it.

What do you think?
I am going to block the lean out pipe, get the lambda sensor back on and see how we go.

Does the lean out pipe 'lean out' the a/f mix under only part throttle or also under full throttle?

Peter

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

The lean out pipe seems to affect the whole range but more so at part throttles. With it connected I also had a leanout when squeezing the throttle into boost (but not nailing it) which was almost impossible to eliminate without getting the WOT mixture too rich. In the end I found that plugging the pipe and redoing the needle was the best way to go.

Terry

website:- http://www.terryhunt.co.uk

Yeah it helped my a/f by blocking it, but then thicker dashpot oil helped too... but in our dyno shootout the 1132 made 106hp at the treads (bananas for you lot :) ) but leaned out to 14.5 and the operator was worried

Pete

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

I had to block mine off as it was causing a lean out from part throttle to boost as Terry describes.

In the 13's at last!.. Just

Mine is lean at full tilt, full boost, 6000 and 7000rpm. Ill scan the dyno dynamics sheet which shows the A/F on it.

Pete

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

Here is a pic from the shootout (I didnt take it, someone else did of one the runs I had. The dyno guy stopped the run and we went and spoke to him... keep going we said, dont worry about A/F now, if she break ill fix her later lol...



Lower lines are A/F (as per guage on the right its up to 14.5) HP is the one above...

Not happy with the run but I guess it made plenty of power for an 1132...

Anyhow, thats my A/F issue at the moment - Thats approx 7000rpm (I think its 6500) dunno

Peter

Edited by pristic on 16th Jul, 2008.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

Did you check out my post on needle polishing?? sounds like thats what you need to do..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=159683

Just a couple of thoughts.. thick oil makes a lean needle look OK whilst ithe piston is moving up quickly (e.g when accellerating hard) but once it slows/stops the true needle weakness shows up. Also make sure that the piston is not hitting the top too early, that will also cause leanoff at high rpm..

what boost are you running??

Edited by Turbo Tel on 16th Jul, 2008.

website:- http://www.terryhunt.co.uk

Hey mate, yep will look into polishing the needle for sure - its on the plans for this saturday.

Im running 15psi
I would love to put the thinner oil back in but have the A/F correct.

Peter

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

With 15psi you maybe want to think of a 12oz spring??

SU dashpot oil is 20wt.

Thinner like 10 or 15 wt is OK but sewing machine oil or 3in1 is not really suitable, there are a lot of stories about thin oil and it comes from the racing boys who use it with really light springs to try to make an SU respond as quickly as a Weber, trouble is they have to compromise cruise and part throttle settings (by making them rich as heck) to get it to work. No problem when driving full throttle around the racetrack, but on the road not so good.... anything thats not full throttle doesn't work well...

website:- http://www.terryhunt.co.uk

Thanks mate! Appreciated. Ill get another spring too. Definately will muck about with needles too (printed your instructions) I will block off the lean out pipe first, check A/F then put a little thiner oil (has 20w 50 engine oil now) and see what the A/F does.
Ill stick in the stronger spring and again see what the A/F does.
If need be, ill polish the needle too...

Thanks,
Peter.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

looks like the needle need a bit of from mid range to the bottom of the needle.

always looking for them bigger bunches of bannanas

ok, blocked off the lean out and rebuilt the carb today, A/F is down to 10 sometimes now, 10.7-11 cruising, up to 13.5 nailing it, and spikes to 14.5 now...

Ill mod the needle... yep, from about 1/2 way down... might lean it out a bit after that, cause its too rich in low revs off boost.

Also, think I blew the headgasket, temp shot up to 105deg C today (VERY cold day) and over the last week has not gone over 80deg C - also have mayo in the cap, but that might be condensation.

Will pull it apart tomorrow and fix.

Pete

1132cc Turbo ~120 bananas ATW - Fun Fun Fun