Boost can be easily set to any level. So you can run low boost for trails and high boost for dunes. On demand power only when you need it.

 

That's a little different application though Shane. The turbo is spooled up at the line and the throttle is never lifted and reapplied till the end of the race

 

This may not work on an atv but don`t they also use twin turbo`s to eliminate lag? A small turbo which is easily spun at low rpm & exhaust pressure plus a large one for the big pressure and hp gain.

I have no real experience in this field but because the air volumes would be small on a single cylinder is there really a lot of lag?

98 Scrambler 500
00 Trailblazer 250

 

on a twin turbo engine both turbos are idenical. they can and do produce both more power and less lag than a single turbo at the same max horsepower level (lag that is).when you drastrically change the boost level you must adjust the fuel and spark curves. this is another plus with efi because you can down load different programs once you figure out what the engine needs at a certain boost level. then fine tune it for the altitude and temp. no this is not practical for anything but the most high dollar sand quads because you could never keep the front end down without a very long swingarm or wheelie bars. then it wouldn't handle in the woods. but it sure makes a good disscussion topic which everyone may learn from. unlike most topics where someone might tell me my raptor is an overrated pile of s**t and thier blaster with a cr500 engine on nitrous with blown shocks is ten times better.no one learns for posts like that. if you're one of those that makes smart *** coments on others topics, shut up and listen you may learns something otherwise park your quad and go back to pokemon. ed i'm sorry if i offended you it wasn't my intention at the start of this topic.

 

The solution here is a supercharger instead of a turbo. I had on a my Mustang and it was a blast. The reason a supercharger has less lag that a turbo is because turbos make power by exhaust gases and a supercharger by the crank. So basically the faster your crank spins the more boost you have.

 

I`ve always thought a supercharger would be the way to go but that seems like it would also be a difficult and expensive way to go. Doesn`t someone make an electric supercharger that puts out about 4 psi boost? Thought I read that in some automotive magazine a while ago.

98 Scrambler 500
00 Trailblazer 250

 

I would have to say that if you really want crazy horsepower the turbo is the way to go. I have been messing with turbo cars since the early 90's and they are a blast. I raced a 92 Eagle Talon TSI AWD in the NMCA quite a few years ago and tore up the EFI class at Norwalk the first year we participated. Now I was not running 6's at 200+ mph but mid 12's on a 13.75 index was enough to have the rules rewritten and some things looked at differently.

As far as turbo sizing, just because a turbo has lag does not mean that it is improperly sized, it just depends what you are looking for. If there is not a little lag then there is nothing worth waiting for... A smaller turbo will give instant spoolup and good low end torque but lack in top end. A medimum turbo will still give quick spoolup great midrange and descent top end. Big and great big turbos will make crazy top end horsepower but lack in the areas of lag and mid range. The bigger the turbo the more air that you can flow and with the proper A/F ratio the more power you can make, it just happens later. If the turbo is too big you can make big power but not have it in a useable area of your RPM band. The perfect sized turbo on a raptor and you could have great spoolup and also a great increase in horsepower & torque.

Personally, I have a stock raptor and I plan on keeping it that way. It has plenty of power for me to have all of the fun that I want to have. Second gear is outrageous in the woods. I have never rode the sand dunes, just strip mines, hill climbing, and woods. I know from experience that I rarely leave anything alone and this time I just want to enjoy it: quiet, reliable & fun.