With you spinning it so slow, I’d say that number could even be conservative, as it’s not even in the meat of the blowers efficiency range. However, you would be above the recommended 18k rpm (pretty common, with few failures), but not by much.
The Resurrection of "The ACCUSER"
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With you spinning it so slow, I’d say that number could even be conservative, as it’s not even in the meat of the blowers efficiency range. However, you would be above the recommended 18k rpm (pretty common, with few failures), but not by much.
I have an ATI stock lower with a diameter of 7.5" combined with a 4" upper. With this pulley combo the SC is only turning 13,875RPM@7400Engine RPM. 7800RPM would net a blower speed of 14,625.
You're correct I'm nowhere near the peak efficiency of the SC. To maximize the SC, I would need a 3 1/4"" diameter upper and 7800 RPM to achieve 17,999.
You're correct I'm nowhere near the peak efficiency of the SC. To maximize the SC, I would need a 3 1/4"" diameter upper and 7800 RPM to achieve 17,999.
I was talking about at 25 psi. Looked at another combo similar and they were using a 15% lower and a 3.5 upper, so I assumed that ratio for your combo at 7800 rpm.
With the 4.2L I don't think you'd have to twist it to 18,000 RPM to achieve 25 psi of boost. I'd expect a a 3.62 or 3.5 upper would turn it fast enough for that boost.
It is something I may try later this year to do. I have a lot of other little things to do to finish the car to my liking first. One is R & R and cleaning a lot of the interior parts to get almost 4 years of sitting cleaned up.
That’s what it took in the combo I compared it to, unless this one just breathes that much better than yours, but I doubt that.
https://www.svtperformance.com/forums/threads/1-416-rwhp-and-kenne-bell-4-7.1025506/
LOL....If I would have realized you were comparing Mark's engine to mine I would have been able to give you a better idea of the differences. Yes, my current cylinder heads flow numbers exceed that engine combo by a good margin. At this point I don't know how high the boost would go with a smaller pulley. Because of the mods done the combo may not build boost as quickly with what would be a standard pulley change for an engine without those mods. Meaning a 1/8" smaller upper pulley may only give me a 1/2 psi boost increase, whereas in a different engine that same pulley size change may increase boost by 1 1/2 psi.
If I remember correctly at that time Mark was running the same piston CR as I am now. The short blocks I believe are almost identical in your comparison, whereas my heads and intake manifold have quite a bit more work invested in them by Tony. I also have more mods in the exhaust system to lower restrictions then that car had at that time.
Bill felt with more RPM and boost that I'd smash through 1300 on his dyno very quickly. Before each pull he's give me an estimate of Hp output that he felt the car would produce with the tune he wrote. And each time the car responded by going quite a bit higher then he expected the results to be. When it laid down the 1100+ he said if Tony says it can do 7500 with no issues that Tony could get in the seat himself to mash the loud pedal. He said he was done and that he felt that there was no need to change pulleys or increase RPM for a number .......I agreed, because it exceeded what I was looking for with ease.
If I remember correctly at that time Mark was running the same piston CR as I am now. The short blocks I believe are almost identical in your comparison, whereas my heads and intake manifold have quite a bit more work invested in them by Tony. I also have more mods in the exhaust system to lower restrictions then that car had at that time.
Bill felt with more RPM and boost that I'd smash through 1300 on his dyno very quickly. Before each pull he's give me an estimate of Hp output that he felt the car would produce with the tune he wrote. And each time the car responded by going quite a bit higher then he expected the results to be. When it laid down the 1100+ he said if Tony says it can do 7500 with no issues that Tony could get in the seat himself to mash the loud pedal. He said he was done and that he felt that there was no need to change pulleys or increase RPM for a number .......I agreed, because it exceeded what I was looking for with ease.
If your heads flow better than his, then it will take even MORE pulley to get 25 psi, not less. So it seems that you’ll definitely need 18k plus, but you’ll also be far exceeding his power level.
T-Bl0ck1943
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@Bad Company
I tried to pm you about where you were thinking of moving in the Shenandoah Valley. I would love to see your beast in person if you have time, thanks
I tried to pm you about where you were thinking of moving in the Shenandoah Valley. I would love to see your beast in person if you have time, thanks
I'm trying to find property in Shenandoah County, unfortunately I haven't been able to find a decent piece of ground to my liking so far. I'm still working on a few little things to finish the car, once I've gotten them done I don't mind meeting up to show you the car
It wasn't me that helped with the valve spring offerings. JDM Engineering is the company you need to thank for that. When JDM developed their Super Stock cam profile they used a .545" lift and had Pac Springs come up with a new set of springs for that lift height.
These engines don't require high lifts to flow big cfm numbers through the heads. I'm not going to give out the cam specs, but they're conservative compared to what was in there in the past.
Timing is conservative during these dyno pulls.
C85 is 21 degrees =1108 RWHP
E85 pump is 18 degrees = 1040 RWHP in my memory is correct
93 pump gas is 15 degrees = 950 RWHP with Engine RPM limited to 6800 to reduce boost climbing any higher than 18.5 psi. This supercharger wants more RPM and starts to build more boost the higher the engine RPM goes. Bill didn't want the car to have much more than 925 to a max of 930 on 93 pump gas, but it built more Hp while exhibiting no knock retard so he didn't make anymore adjustments to this tune.
Ah, ok.
I thought spring bind was one of the issues you highlighted in the last thread. Leading to JDM speccing new springs.
I thought spring bind was one of the issues you highlighted in the last thread. Leading to JDM speccing new springs.
Spring bind was an issue with the first engine. The camshafts were radical with .575" lift on the intake and .566" lift on the exhaust. This put the exhaust valve spring into coil bind according to Pac Springs with the part number spring used. The new springs that JDM Engineering had designed by Pac Springs are maxed out at .550" lift on both the intake and exhaust.
JDM had Pac design the new spring for an easy installation of their Super Stock camshafts, I had nothing to do with this. The issue and the reason I believe JDM and Pac did this was so the stock valve spring retainers could be used. Prior to JDM and Pac coming out with this new spring there was only one other spring available from Pac for high lift cams in these mod motors. It required the installation of 2 different valve spring retainers to stay out of coil bind. If the installer wasn't careful he could get the retainers swapped in backwards and really go into coil bind on the exhaust valves
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I have JDM ENGINEERING cams as well,but my motor is not built yet.I read some years ago that they JDM had a COBRA JET with the 5.4 in it,and with their cams they went up to 8000 RPM!!So,your 7800 RPM is very much believable .How did the trans act at 7800 RPM was it smooth?
I don't know what you'd call it now. None of the modification to lose weight have been performed. I believe I stated earlier that my wife's health is poor, she doesn't want me to go to the Texas Mile for fear of an injury on my part would cause us difficulties in caring for each other. When I got the car back together this last time I found things done incorrectly by the last shop that worked on it, particularly with how things were routed and the workmanship of the wiring of electrical modifications to the car that I felt were a major safety concern. To fix these things the car needed to be torn down, also the routing of the hoses for the heat exchanger system was poorly thought out and executed. I'd met Ryan and Tammy Hargett of HAP during Hot Rod Drag Week at Virginia Motorsports Park a few years ago. I was intrigued by the cage in the car and the fact that all of the creature comforts like A/C and heating system were still installed and functional in the car with the 25.3 cage and its cross bar in the dashboard. Ryan explained how they utilized the existing factory Ford lower dashboard mounting system and incorporated it into the roll cage to retain everything in the dashboard. Ryan and Tammy allowed me to sit in their car during those two days they were at that track to see how I liked the cage. I still want to go to the Texas Mile, the rules have gotten harder to comply with as the speeds have increased at this event. This car should be able to achieve more than 230mph without too much trouble. The rules for those speeds require a NHRA 25.3 cage regardless if the car is street driven or is a full blown race car. As a street car I'm l was lucky if I drove it more than a few hundred miles a year, so I thought put the cage in it and if I ever get the chance to go to "The Mile" it wouldn't be something I have to do to modify the car to do.......it was already done waiting on me. So it is a "Badass" street car with a full boat race suspension and roll cage at the moment
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