Well, finally made it to the track after a long winter break. The dyno tuning and vacuum pump have definately made a measurable improvement. Sundays weather was not great with fair to poor air conditions.

The previous best last season in true street trim was 10.81 @ 123 with a 1.49 60'. All time best in "race trim" is 10.66 @ 125 with a 1.47 60'. That was on 9 x 30 radial slicks and race mufflers with turn downs.

Yesterdays runs. To date street tire/full exhaust bests are noted in bold.

Run #1
1.521 60'
4.414 330'
6.879 660'
10.855 1320'
122.55 mph

Run #2
1.513 60'
4.392 330'
6.840 660'
10.782 1320'
123.65 mph

Run #3
1.488 60'
4.350 330'
6.795 660'
10.724 1320'
124.23 mph

Run #4
1.499 60'
4.364 330'
6.796 660'
10.699 1320'
124.94 mph

I'm confident that the car can and will run 10.50's with better track and air conditions. The car was shaking the tires on each run today. Most racers I spoke with were slower by a tenth to two from last weekend at this same track (our local "junky" track.

Nice graemlins/thumbsup.gif

graemlins/thumbsup.gif

You werent at Cecil County, correct?

Do you stage Deep or Shallow?

Originally posted by Motor Martyr:
You werent at Cecil County, correct?

Do you stage Deep or Shallow? This event was at 75/80 Dragway. The event I ran was our local MSRA heads up street car series in the DOT class.

I staged shallow on the .400 pro tree. Should have deep staged for R/T, but didn't want to sacrifice any ET.

Don't laugh at this question but what is the purpose of a vacuum pump? How would it improve performance? :confused:

Darren, The vacuum pump pulls a vacuum on the crankcase and allows the rings to seal better. In most high dollar race engines very low tension ring combinations are used with a thin upper ring. The pump helps the rings seal giving more power. Care must be exercised to not get too much vacuum however as this vacuum also starves the valve guides of needed oil somewhat.

that car flies, nice job graemlins/thumbsup.gif

Thanks Harold. smile.gif

graemlins/thumbsup.gif graemlins/thumbsup.gif graemlins/thumbsup.gif

10sec
is there still a cow pasture at the end of the track?

Originally posted by 1968 hot rod:
10sec
is there still a cow pasture at the end of the track? Probably, but not really sure. I'm too busy to look while squeezing the binders down hard to get stopped for the last turn around with that dang short & bumpy shutdown area. How Bunny Burkett ran an alcohol funny car there is beyond me :eek: .

http://www.hobbystage.net/camaro/camaroracer/1053300074-001914.jpg

Todd, did you have to do anything special to the engine to get the pump to work? i hear the seals have to be installed backwards to keep from getting them sucked into the pan. is the pump vacuum adjustable and if so how much vacuum does it pull? do you use the pump on the street and does it require a catch can? also how much power do you think it was worth? thanks Dave

Originally posted by sheetmetal:
Todd, did you have to do anything special to the engine to get the pump to work? i hear the seals have to be installed backwards to keep from getting them sucked into the pan. is the pump vacuum adjustable and if so how much vacuum does it pull? do you use the pump on the street and does it require a catch can? also how much power do you think it was worth? thanks Dave I didn't install the pump for power, rather to control internal pressure from excess blowbye. The engine has some cylinder wall scratches from a previous roller lifter failure. That created high internal pressure which caused some mysterious oil leaks.

The pump I use is a GZ Motorsports Sportsman Plus pump. With the motor sealed (no breathers), the pump created 10" at idle and 13" at a 3000 rpm cruise...no WOT passes. I run a McClintic relief valve which limits the vacuum to 11" at WOT on track. It pulls 5 to 6" of vacuum at idle.

My engine uses all normal seals and gaskets. I also use standard tension piston rings. If this were a specific race only motor, I'd probably use the low tension rings and the special seals (which are very expensive BTW).

I'm told typical vacuum pump installs are worth between 20 to 30 hp, but can be worth more depending on the combination. I was more worried about keeping the oil leaks in check and if the pump helped with more power, then so be it. I wasn't holding my breath expecting to see more power. At this point, the ET improvement is likely due to the 25 RWHP we found on the dyno last fall before the vacuum pump was installed. Eventually I'd like to put the car back on the dyno and make pulls with and without the VP belt to verify any measurable gains.

At this point, I'm anxious to get on a well prepared track with good weather conditions. Likely, that will have to wait till fall at this point. Would really like to slip down to MIR which I have not had the opportunity to race at.

i will be following your progress with this pump set up. im using a middle weight tension oil ring set up in my S/B. my mph seems down for the hp my engine dynoed and am looking for ways to raise it a bit. my cranking compression seems a bit low as well so i may give a pump a serious look, providing i dont have to pull the engine for the different seals. Dave