11.90 Raptor jetting on sleeved 33mm?

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11.90 Raptor jetting on sleeved 33mm?

Postby Kern Family Racing » Thu May 10, 2018 8:28 am

I am curious to see what others are running as far as jetting for those that have a sleeved 33mm. Right now we just changed to a billet head and the temps are higher than with the stock head. I also question the accuracy of the Mychron 3 and the infrared scanner says it is about 35 degrees cooler. I digress. Finish line temps are areound 430 degrees and 6200 rpm trap rpm. The car is leaving at the 280-290 degree range and is does not miss or pop down the track. The motor has an old Dyno 108 cam so it is not screaming down the track by any means. My concern is that with the new head, that I may be starving it. My sleeved 33mm is set at 205 main, 65 pilot, plug on pilot air bleed, and 0.5 on main. Does that sound like an ok setup or should I try and push a little more fuel?
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby rolltidechris » Thu May 10, 2018 1:55 pm

Per Huddleston...this is the setup you should start with on a sleeved 33....see below

Pilot- .055
Pilot Air- .8
Main - 195
Main Air- .7
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Kern Family Racing » Thu May 17, 2018 9:43 am

Just as an FYI. Removing the sleeve made no difference at all on the engine. Jetting stayed the same and the plug looks good with the overall result that the car reacts the same. I am assuming that volumetric efficiency is at work here. The engine will not take any more air than it needs unless it is forced into the cylinder. I will say that our consistency improved a little bit taking it out, but that may just be coincidence.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Kern Family Racing » Thu Jun 07, 2018 9:24 am

Well, I have made some progress with finding clutch issues and it is much smoother through the entire run. I am now battling a stumble off the line. My 33 still has the idle mixture screw in it and I have played with it with no luck. I was originally at a 60 pilot with a plug in the air bleed without an issue. I pulled the sleeve out and it didn’t make a difference. I am now at a 70 pilot and .5 air bleed which has just a small stumble about 20 feet out. I have a 205 Main jet with .7 air bleed. This seems way out of whack for “normal” 11.90 motor. I checked for vacuum leaks to be sure something like that was causing the issue. Could I be missing something else? I have an adjustable timing bracket on the coil, but I am a bit timid to adjust it.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Pool Man » Thu Jun 07, 2018 6:23 pm

What have you done to the idle screw? Adjustments? How far in or out? Stumble at the hit still could be the clutch
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Kern Family Racing » Thu Jun 07, 2018 10:17 pm

I moved things back to a more “normal” settings. I moved the pilot back to a 0.55 and a .5 air bleed and a 200 main and a .7 bleed. It took care of the bog/pop, but it doesn’t idle very well. I am not sure about the idle mixture screw or where a normal setting should be. I will play with it tomorrow to see if I can get the idle a little more stable. Is turning the screw in rich and out lean?
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Kern Family Racing » Mon Jun 11, 2018 2:58 pm

It made it down the track without any stumbles or pop and sounded very clean. I am really a bit concerned about cylinder head temps, but I also question the accuracy of my Mychron 3. I have an infrared scanner and it shows 40 degrees cooler than what the Mychron is showing...I digress. We are staging and leaving about the 260 degree mark and finishing about 430 or less. The engine does not seem to mind and runs fine. Should I be concerned? Even with the 70 Pilot and a .5 air bleed, we would always seem to end up about the 260 degree mark when he launches. Just want to make sure I am not starving it.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Pool Man » Mon Jun 11, 2018 5:14 pm

Both temps seem a bit hot to me. I would think they should be around the 135-150 idle and 350-375 at the stripe.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Kern Family Racing » Sun Jun 17, 2018 9:34 pm

Well, this weekend was weird and I am a bit concerned I may not be getting good pilot jets from Viperizer. I tried to fatten the car up for the heat this weekend and it kept acting like it was leaning out. I went clear up to a 70 pilot and the head temp didn’t change. Which, if you read this thread, you will see my CHT runs hot. I pulled the pilot out and compared it to one of our neighbors the same size and ours was visibly smaller looking through the hole. I am concerned that I have been getting defective or gas jets. Has anyone else experienced this with Viperizer? I have been fighting weird issues with the carb and I have gotten all of my jets from them?
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Tack » Mon Jun 18, 2018 12:46 am

I had the same issue a while back. Went from a 59 to a 57 to get a fraction more idle temp and the thing shot to over 200f in about 10 seconds.
I know its a PITA but I would suggest ditching all of those jets and getting a complete new set so that you can rule out poor workmanship.
We have had the same issues with all sorts of jets for big cars too, including alcohol and nitro from different suppliers.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Kern Family Racing » Mon Jun 18, 2018 12:24 pm

Any recommendations on a good supplier of alcohol jets?
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Ten5TireDad » Mon Jun 18, 2018 12:32 pm

Craw's sells the jet block and assortment. Great item to have comes with main and pilot jets, and air bleeds.
When I ran a sleeved 33 we had a 59 in the pilot and for hot weather like now I ran as big as a 205 main, and as small as 180 in the cold
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Kern Family Racing » Mon Jun 18, 2018 2:05 pm

I am pretty sure this is why my CHT is hot and gets there quick. I just can’t believe no one has called them out on bad jets before now. I am going to tell them they have an issue.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Tack » Tue Jun 19, 2018 2:05 am

I have used the JR Race Cars jets that come as a kit in the billet block and found them great.
I am sure that if you purchased from one of the site sponsors you would be fine. Craig at Blossom has excellent service!
Just a tip, buy everything that you think you might need in one hit giving yourself a range to choose from.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby WILD BILL » Tue Jun 19, 2018 6:21 pm

I did talk to him about his carbs and jets shortly after he bought the company.

I guess he didn't believe me.

I always buy my jets From JR Race Car.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Kern Family Racing » Tue Jun 19, 2018 8:54 pm

I hate to throw them out, but I would have to buy a precision drill bit set and hope I could drill them out correctly.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Kern Family Racing » Thu Jun 21, 2018 12:04 am

I have confirmed that all of the Viperizer pilot jets are junk. They stamped them, but are not drilled all the way through and the holes are all the same size in the middle. I put a known good 55 jet in and the CHT never climbed over 175 at idle. No more jets from them! The whole time, this has been my issue!!!
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby Ten5TireDad » Thu Jun 21, 2018 10:13 am

Your best bet now it toss them in the trash, and start over. You found a problem, so replace them and anything else you think is questionable.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby WILD BILL » Thu Jun 21, 2018 3:46 pm

FWIW, I would trash em also.
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Re: 11.90 Raptor jetting on sleeved 33mm?

Postby oldsdigger » Tue Jul 17, 2018 12:51 pm

I didn't trash mine, I bought a miniture drill set that i could mic and use to determine what the hole size was, then i either relabeled and made a key that showed what the label said and what the hole size was. It save $$, but can be a pain. Quality is bad on these items from Vip.
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