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Just spent a few days in Willow Springs,NC on the dyno at Performance Specialties. We spent a whole day and a half changing jets changing carbs and headers and this was the best setup. I have a Carb Shop dominator that I have had for about 10 years that we tried first. It was not pulling the fuel up at about 7000rpms+ that Doc thought it should. So we swapped to my SV1 and it went from 280lbs of fuel to about 320 to 330lbs of fuel up top. I had my 3 step headers on the dyno also(2 1/8 X 2 1/4 X 2 3/8 X 4" merged collector). After we made this pull I wanted to make sure the headers were not a problem so the only other available was a set of 2 3/8 X 2 1/2 with a 4" collector. It dropped 50 ft/lbs of torque right off the bat. Needless to say I felt quiet a bit better about my headers at that point. I don't have a flow sheet on these heads, so I'm not sure what they actually flowed. I do know the heads have Pac 1228 springs installed with 310lbs pressure on the seat and 900 lbs open. Titanium valves and the copper beryllium valve seats. I have included the cam I have in there now. The markings on the card are with it in the other motor. I think the cam is installed about 1 degree retarded. I am also using a Sniper X intake along with Sniper X heads, Callies Magnum XL crank, Jesel 1.8 rockers. Oliver billet rods. Crower lifters. Star Machine vacuum pump. I would be interested in any feedback or suggestions that anybody might have. I had this cam, I have been told it was close but could use a little more exhaust duration. Some of the notes on the dyno sheet were not updated but this is with the SV1 and using Q16 gas as well. Used C25 and 92 main jets and changed to Q16 and ended up with 98 jets and no change to the high speed bleeds(.035"). Doc said the only other change he would have made was to go to a .036" bleed because it was getting rich up top.

I would be interested in any feedback or suggestions that anybody might have.
I have been al over the place in this post. Sorry for being long winded!!









 

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.035 High Speed is incorrect for Q16.... if it made good dyno numbers like that, the carb might not be calibrated right for the Q... but .026 is typically where Q wants to be for racing on the racetrack.
 

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I'm no dyno expert, but when we dyno'd mine they wouldn't make a pull till the oil temp was 180 degrees, every pull.
 

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Regardless of what the numbers were, was the HP/TQ curve smoother with the 2-step headers?

The dips in the TQ curve are likely from the header primary size/lengths. What are the lengths of each of the header sections?

Jason G.
 

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Intake tuning will have a significantly larger effect on HP/TQ numbers jumping around than header lengths. The intake runners will hit different harmonics through the RPM range which will create the local peaks, in an application like this typically the 3rd 4th and 5th with the power peak being at the 4th.
 

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Intake tuning will have a significantly larger effect on HP/TQ numbers jumping around than header lengths. The intake runners will hit different harmonics through the RPM range which will create the local peaks, in an application like this typically the 3rd 4th and 5th with the power peak being at the 4th.
I generally agree, but have seen other similar sized engines with the same heads and intake that don't have that problem.

Wizzard,

What valve springs, rockers, and pushrods are you running?

Jason G.
 

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I generally agree, but have seen other similar sized engines with the same heads and intake that don't have that problem.

Wizzard,

What valve springs, rockers, and pushrods are you running?

Jason G.
I have to agree, some of the numbers like at 6700 and 7300 certainly seem out of place....
 

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I generally agree, but have seen other similar sized engines with the same heads and intake that don't have that problem.

Wizzard,

What valve springs, rockers, and pushrods are you running?

Jason G.
Sorry, went back and read the original post.
 

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If the dyno is on a controller, it could be the dyno surging. Ive had that hapapen before.
 

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Discussion Starter #16
•Compression 14.4 to 1

•Made about the same hp but torque dropped from 790's to 750's

•The Q16 calibration from Patrick calls for changing mains from 96 to 99 and high speed from .035 to .031. I found the a dyno pull sheet with those changes and I believe it looks a little smoother. I will post it on here next time I get a chance. I don't remember exactly why we went back with the .035, other that Doc's suggestion while reading the dyno info.

•The headers are 10" long before the next step with the final step the remainder to get to collector. So I believe they go 10 x 10 x ? I will have to measure to get exactly what length the last step is.

•I do have the Smith Brothers pushrods with tool steel tips. 3/8" with .147" wall thickness.

•Alternator bracket is one my brother had made at his job using a Moroso bracket for a template. I tossed the belt once and it bent the thin bracket so he made this one. Looks pretty sweet in my opinion.

•Doc did say that he will have the dyno down for about a month to install new water tanks outside and take the assembly and check to see if he needs to have it rebuilt or freshened. It is a Depac dyno controller also.
 

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I agree that it looks like the dyno surging is what's freaking those numbers out.

If you were running it all day, heating up the water could be a cause dependin how big his tank is.

It would be nice to have more ex duration , Comp has a decent 304 exhaust lobe and/or wider lobe separation like 113 and instal it at 109-110 if you want to bring the rpm range and hp up a bit.
 

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Just spent a few days in Willow Springs,NC on the dyno at Performance Specialties. We spent a whole day and a half changing jets changing carbs and headers and this was the best setup. I have a Carb Shop dominator that I have had for about 10 years that we tried first. It was not pulling the fuel up at about 7000rpms+ that Doc thought it should. So we swapped to my SV1 and it went from 280lbs of fuel to about 320 to 330lbs of fuel up top. I had my 3 step headers on the dyno also(2 1/8 X 2 1/4 X 2 3/8 X 4" merged collector). After we made this pull I wanted to make sure the headers were not a problem so the only other available was a set of 2 3/8 X 2 1/2 with a 4" collector. It dropped 50 ft/lbs of torque right off the bat. Needless to say I felt quiet a bit better about my headers at that point. I don't have a flow sheet on these heads, so I'm not sure what they actually flowed. I do know the heads have Pac 1228 springs installed with 310lbs pressure on the seat and 900 lbs open. Titanium valves and the copper beryllium valve seats. I have included the cam I have in there now. The markings on the card are with it in the other motor. I think the cam is installed about 1 degree retarded. I am also using a Sniper X intake along with Sniper X heads, Callies Magnum XL crank, Jesel 1.8 rockers. Oliver billet rods. Crower lifters. Star Machine vacuum pump. I would be interested in any feedback or suggestions that anybody might have. I had this cam, I have been told it was close but could use a little more exhaust duration. Some of the notes on the dyno sheet were not updated but this is with the SV1 and using Q16 gas as well. Used C25 and 92 main jets and changed to Q16 and ended up with 98 jets and no change to the high speed bleeds(.035"). Doc said the only other change he would have made was to go to a .036" bleed because it was getting rich up top.

I would be interested in any feedback or suggestions that anybody might have.
I have been al over the place in this post. Sorry for being long winded!!









Your depac stuff different than what i use.Where is your correction listed at and air inlet temp,etc?I dont like dynoing with pipes on headers ,some engines makes huge changes to them.You can never get decent numbers with big inch stuff.The chimney system dumping out of open headers is way better way to dyno.The acceleration rate of that engine in time is all over the place ,i dont know how you could ever duplicate numbers or know if you improved anything.I m not trying to be negative on your system just saying what i see.
 

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Discussion Starter #20
I don't know exactly what model the Depac system he uses is, but he does have correction factors and air temps and lbs/hr of fuel. They are just not printed on the dyno sheets. I'm not familiar with all the different connections available for these dynos, be it exhaust or routing of the oil pressure or vacuum sensing lines(the two small braided lines running over the top of the sparkplug wires) but this is the third motor I have had on his dyno in the last 10 years and this motor is the most radical of the three. Do you have any pictures of your exhaust chimney? I would like to see them if possible. Thanks for the feedback. Please keep them coming.
 
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