Bender Guys Help

[Rx1M5]

I'm helping a fiend of mine set up his Bender turbo and have a few Questions.

1. How much affect on main jet sizing does the pitot jet have? Can it change the jetting 1,2,3 or more main jet sizes or is that even how it is meant to work. He has a selection of jets from 0 - 500 but for sure the last time out it was way lean. I don't trust the stoich gauge on the sled and the plugs are too white for my taste plus it was lean popping like crazy.

2. We are adding an intercooler ( Thanks Turbo Tim) is that going to affect the jetting. If so by how much? Should improve the detonation I'm thinkingn

3. Running 1/2 pump premium 1/2 C111 is that enough octane?

4. The 6- 12 lbs boost switch doesn't seem to make any difference in pull or performance. Should we just lose it and set the rod to 10-12 lbs or get a variable boost controler? Are those switches crap?

More questions to follow but this is a start. I know his sleds not right cause my CPR sled spanks it bad and I've seen some Bender sleds working really well.

Thanks

Rx1M5

 

[maxdlx]

JMO

set your jetting stock, and adjust it with the charge tube jet. You may need to get 600 and 700 jet. We ran the one in our group all week long at 6 to 8 lbs boost on 93 octane no problems. He has the twist type controler and loves it. I'm sure once he gets back from getting his wisdom teeth pulled he will chime in. We had his all messed up, once we got back to stock jetting, and used the charge tube jet it was a ok . Maxdlx

 

[BigDog05]

At 2200-2900 ft elevation I'm running a 400-500 pitot for 10 lbs boost and a 300-400 for 12lbs. This year has been around 0-10 F all the time so I'm been running on the smaller side pitot jet. Last year when it was 25-30 F all the time I was on the higher side with the pitot.

Remember that a smaller pitot jet means richer mixture and larger pitot jet means leaner mixture.

If you would change to a wideband A/F, you will see that a 100 jet change is good for about a .5 change in air fuel reading.

You may have a kink in the line going to the 2 position switch. Do you have a boost guage? If the line is kinked, you will be getting the same boost no matter what position the switch is in.

I use a Halmann Pro manual controller and it is good for 1 lb of boost change for every turn. It works fine for me, but I only run 10 -12 lbs of boost .

I always had lean midrange popping. The first thing I did was get rid of the plastic T's and replace with billet ones. Then I raised the needles 1 notch richer, and went to 20 pilot jets at 2 turns off seat. I also added a second line from the intercooler to the vents at the rear of the carbs. This helped all 4 slides open at the same time under low and part throttle
conditions. I also run stock main jets.

If you have a leak in any of the connects, the sled will not make power.

 

[Rx1M5]

I should have added that we ride at 6-8000 feet usually at temps just below freezing. Is this pitot something a guy typically changes everyday or is it more of a set and go thing.

We have the billet tee's now and will be putting them in. As far as main jets go I'm not sure what's in there as we were waiting for the tee's to arrive as well as the billet carb caps prior to tearing it down.

He re routed the boost switch line so I believe it is kink free. I was thinking of moving that switch next to the turbo and getting rid of all that line altogether. I have a manual boost controler on my sled and it works pretty slick.

Thx

 

[BigDog05]

I carry a set of jets in my bibs, 100 - 800. Change as needed. It is a little close getting your had under the charge tube, but only takes 2 minutes.

 

[BigDog05]

I have my boost controller coming out the right side exhaust cover. There is only a couple inches of line to the turbo, and a couple inches to the wastegate controller.

I originally had it coming out the fake exhaust on the right side, but have since added the quieter dual exhaust.

For whatever reason, my sled just needed to be a little richer in the midrange than a lot of other guys.

 

[maxdlx]

hey

How do you like that quiet exhaust. i think it is a must, those things are loud. Maxdlx

 

[Rx1M5]

I also added a second line from the intercooler to the vents at the rear of the carbs. This helped all 4 slides open at the same time under low and part throttle
conditions. I also run stock main jets.

OK if I remember correctly the 2 tee's at the back of the carbs are going off 1 line to the pitot jet. I may have that wrong as I'm not where the sled is right now but if that is the case how do you replumb those and keep the pitot jet thing? My CPR is plumbed right to the intercooler.

Rx1m5

 

[BigDog05]

Rx1M5: You have that backwards. Under the intercooler are 2 fittings. One goes to the fuel pump regulator. The other one goes to the vents at the rear of the carbs.

Add an extra line to the rear carb vents. You will set if you blow into the single line going to the carb vents, that the two left side vents will open quicker and higher that the other two.

The line from the pitot jet goes to the billet T's you are getting.

Also, see if you can PM spray 25, he is the guy that figured out the extra line and was one of the first to have a Bender turbo. Also I think he rides at higher elevations like you do.

 

[Rx1M5]

Thanks I see that now.

 

[77srxdude]

Remember that a smaller pitot jet means richer mixture and larger pitot jet means leaner mixture.

I was under the impression that the Pitot jet bleeds off air - so a larger jet like a 700 bleeds off more air leaving you richer and a 400 - smaller jet, bleeds off less air (so more air makes it to the carb) making you leaner.

 

[Rx1M5]

Remember that a smaller pitot jet means richer mixture and larger pitot jet means leaner mixture.

I was under the impression that the Pitot jet bleeds off air - so a larger jet like a 700 bleeds off more air leaving you richer and a 400 - smaller jet, bleeds off less air (so more air makes it to the carb) making you leaner.

OK now I'm confused. How about just getting rid of that whole pitot thing jetting the sled right and be done with it. I never change my jetting on my CPR kit and my A/F's really don't change very much. I kinda like simpler the better. The whole thing seems like a PITA to me is it really that good?

Rx1M5

 

[BigDog05]

77 srxdude: If someone can give a better technical answer than me, please do.

You are correct about bleeding off air with a larger pitot jet, but it actually works in reverse.

The smaller jet bleeds off less air, therefore pressurizing the carbs more, causing the carb to think that it is jetted richer, because of extra pressure in the float bowels.

Smaller pitot jet = richer mixture, larger pitot jet = leaner mixture.

 

[Turbo Tim]

After everything is plumbed right , Try plugging the pitot jet off completely if it is still lean , this will richen it up .

 

[77srxdude]

Thanks BigDog

Definitely do not go by what I say - this is how I interpreted it from the guy I bought the kit from - that is why I am asking. I thought I understood it but I clearly don't. Sorry if I am causing any confusion.