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Huge stumble WOT from idle

I
Jan 4, 2011
760
136
43
Saskatchewan Canada
09’ m8, aerocharger turbo, boondocker control box.

Idling, smash it wide open, and it sits there bogging at around 4,500 rpm, slowly picks up then its normal.

Idling, feather the throttle, blipping it, then smash it wide open and it’s a rocket.

Where does a guy look, tuning? Clutching?
 
J

jim

Well-known member
Nov 26, 2007
1,014
635
113
Boise
Turbo has to spool up. You could raise the engagement rpm...but smaahing it wide open on turbos doesn't work well. Tou also have a heated batch of air in the intake. I had problems getting on the pipe at all with my turbo until cold air intake...that helped a bunch. But, you cant just smash a turbo wide open in general.
 
I
Jan 4, 2011
760
136
43
Saskatchewan Canada
Turbo has to spool up. You could raise the engagement rpm...but smaahing it wide open on turbos doesn't work well. Tou also have a heated batch of air in the intake. I had problems getting on the pipe at all with my turbo until cold air intake...that helped a bunch. But, you cant just smash a turbo wide open in general.

Part I find confusing is if it anywhere above idle blipping the throttle, no boost, and smash it open it goes like snot. I have a jerry rigged cold air intake with white 3” pvc fittings lol. I found that helped a lot, but maybe it’s just something I need to live with.

I guess going from a N/A race sled where I can go WOT from idle and have it sit at the power and spoiled me a bit lol, oh and having a speedwerx supercharger on my Proclimb wouldn’t help either.

Does it make a hollow woooooaaaat sound or more of a gurgle slobber sound.

Prob reeds though

Lol the wooooaaattttttt-ggggerrrrrrraaaaaaaaaaaaaaaaaaaaaaappp sound. I’ll stick my scope down in the throttle bodies to take a peak at the reeds, forgot I never checked this sled only my Proclimb I did.
 

Sunvang

Well-known member
Lifetime Membership
Dec 4, 2010
1,043
379
83
35
Norway
Turbo has to spool up. You could raise the engagement rpm...but smaahing it wide open on turbos doesn't work well. Tou also have a heated batch of air in the intake. I had problems getting on the pipe at all with my turbo until cold air intake...that helped a bunch. But, you cant just smash a turbo wide open in general.

I have to disagree. No problem going from idle to WOT on a turboed sled. Just need to have the right setup. Ive had several Polaris sleds with Boondocker, Silber and MTNTK turbo kits. Tune the fueling snd clutches well, and its no problem going from idle to WOT. Some turbo charghers use longer to spool, but it shouldnt bog, stumble or fall on its face.


Has the sled always been like this? What gen Boondocker fuel controller?
 
I
Jan 4, 2011
760
136
43
Saskatchewan Canada
Look at reeds, sounds lean.
Try throwing a ton of fuel at the bottom in mid and wot

3600 lo. 0
3600 md. -3
3600 hi. -10

5000 lo. 0
5000 md. -7
5000 hi. -13

Changed the negatives to positives and still did it. Engagement is around 4000rpm, when I crack it open it stops at like 4200 sits there, basically until boost comes in it seems, which take like 1 full second.

I never got around to checking the reeds. We had some snow here at home so I played around.
 
I
Jan 4, 2011
760
136
43
Saskatchewan Canada
I have to disagree. No problem going from idle to WOT on a turboed sled. Just need to have the right setup. Ive had several Polaris sleds with Boondocker, Silber and MTNTK turbo kits. Tune the fueling snd clutches well, and its no problem going from idle to WOT. Some turbo charghers use longer to spool, but it shouldnt bog, stumble or fall on its face.


Has the sled always been like this? What gen Boondocker fuel controller?

That’s what I was thinking, I’ve seen other turbos guys can go wot and it’s a little slower then a stock take off, so that’s why I was confused.

Sled has been like this since I bought the sled I robbed the motor and turbo from.

I forgot to write down the generation of controller. It’s a pump gas no aux injectors, has the psi-h psi-l settings. It’s an all grey cover around the screen with red outlines buttons.
 
X
Oct 8, 2009
308
199
43
The problem is the turbo veins...they are too tight. Open them by extending the adjustment rod into the turbine housing. An acid test is to make a change and if it gets worse, you went the wrong direction. What you are experiencing is excess back pressure choking the motor when the veins are closed that corrects as the veins open. The vein setting affects spool, but I found a looser setting is better all around than trying to eliminate every bit of lag since you do not ride from stop. Every turbo kit will lag a little from a stop because the turbo has to spool up since there is no load on the turbine at idle.
 
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