Drags

nomadtrash · Post by **nomadtrash** » Tue Nov 15, 2005 2:11 pm

Will,

You should slap that cam you bought from me in the motor. It was like night and day when compared to the B-Cam that I had in my motor. Before you go tearing the thing apart you should at least try the cam and see how it runs. I predict a big "Holy Crap! this cam Rocks!"

nomadtrash · Post by **nomadtrash** » Tue Nov 15, 2005 2:25 pm

I ran a 10.05 in Tetanus in the 1/8 with a slipping clutch, worn out race tires (no traction), and over 300 pounds of lead ballast weights. The total weight was well over 2300 pounds. This calculates to around a 15.6 in the 1/4. If the clutch hadn't been slipping and I had even decent street tires I could have been in the mid nines which is high 14's in the 1/4.

I am in the process of installing a supercharger on my KA24DE.(400 hp goal at 14 PSI) The weight is 1800 pounds with driver and I have 23x12x13 slicks in the back. I expect 9's in the 1/4 as soon as I get it put together.

http://www.nationaldrivetrain.com/calcs/dragcalc.html

nomadtrash · Post by **nomadtrash** » Tue Nov 15, 2005 5:02 pm

I supercharge because of the nature of autocross. I need instant torque and horsepower. I can't wait for turbo lag. The KA24DE has a super flat torque curve. It allows me to not have to shift as much because with gobs of torque at the low end I can lug through corners without shifting. A turbocharger increases boost as the rpm's rise. You get less effect from the turbo at low rpm's and more at high rpm's . I would have to shift more to keep the rpm's up and keep it on the boost. A supercharger basically takes you horsepower and torque curves and copies them higher up on the graph. You have the same character or powerband but at higher output levels.

It is true that a supercharger has some parasitic effect and may not be able to generate the turbocharger peak horsepower numbers. I think that with the supercharger I can get to the 400 hp mark at 14 psi. Could a turbo get more? Probably, but how much more do you need in an 1800 pound (with driver) car?

Nines in the 1/4 is fast enough for me.

I am also getting ready to install a BikiRom programmable computer in my KA. It is a add-on daughterboard that works in just about all Nissan OEM computers. It hooks to a laptop via USB cable. It is completely programmable. Basically, it is like a Jim Wolfe computer but is programmable like a megasquirt. I can change injectors, MAF, compression ratio, ignition curve, etc... without needing Scott or Jim Wolfe to burn a custom chip for each modification. I am trying to get a sonsorship deal with them. I would love it if all of you called or e-mailed Lucas at BikiRom and told him how you heard of them.

Later,

Dave · Post by **Dave** » Tue Nov 15, 2005 5:57 pm

A quick trip to a dyno could prove that, and someone very skilled in the art of tuning carbs (why I have EFI) would probably net another 50hp unless there is something wrong with the build up.

You got that right Travis! I went from 151 Hp to 176 Hp at the rear wheels with nothing more than adjusting timing and fuel pressure. My base timing was 5* retarded from where it should have been (I must have read one notch off on the pulley! Doh!) and I was running waaaaaay rich (10:1 AFR). Once I got the base timing up to 16* advanced and leaned it out to 12:1, I picked up 25 Hp.

SLOroadster · Post by **SLOroadster** » Tue Nov 15, 2005 11:54 pm

A little tuning is all I can do. The carbs might need a rebuild, and the head might need to be gone through more carefully. I had it apart when I bought the car, the machinest said the seats and guides looked good so I replaced the springs, seals, rockers, cam, and put it all back together. I jumped in it the other day and noticed a puff of blue smoke on startup. I don't have a leak down tester to do a compression test. I don't know. The same guy took a quick look at the head when I had the engine apart a year ago, but said that it looked ok. I'll dyno it anytime, but I have no extra jets that I can swap into the carbs, so it would be little more than a base pull.

Andy, as for that cam, according to Elgin, it is a stock cam. I tried to explain that it should be different from the B cam, but they swore up and down that it was the same as a B cam. I'm still researching what happend, when I have it back in my hands I will pull out the calipers and measure my B cam and see if yours is indeed bigger. If thats the case I will regrind it to what I should have now. I think my current cam might have been cut for a 1.5:1 rocker ratio, however I'm not sure.

Will

Dave · Post by **Dave** » Wed Nov 16, 2005 10:33 am

Will,

Many of the dyno shops will run specials where thy give you something like 3 pulls with no tuning in-between. It attracts the car club guys and gives you an economical way to get some baseline numbers. If I recall, I paid $30 for 3 pulls at my old dyno place in Portland. If your local place will only rent the dyno out by the hour, wait until you have a big handful of jets and can go do some serious tuning. Some places charge an extra $10 or so for the Air/Fuel monitoring. Do it!! It's a complete waste not to, especially if you're tuning. Don't forget your timing light. You'll be amazed at how many pulls you can get in an hour. I'll be you could run through 2 dozen different combinations of jets, timing, etc. in an hour session. Aside from just tuning for peak Hp, you can also work out any part throttle drive-ability issues. It'll be just about the best money you've spent on the car!

SLOroadster · Post by **SLOroadster** » Thu Nov 17, 2005 11:46 pm

I haven't found any dynos around here. I know Z car garage just got one, but I don't know how much Rob charges, or if its up and running. The car really doesn't have any driveability issues, (needs some upper a arm spindles, but those are sitting on the desk). Heck I'd jump in it and drive it to the east coast, if I really wanted to. I do know that tuning on a dyno is a usefull thing to do, I just need everything to fall into place to get it done. Right now I'd bet I'm one fuel jet too large, and one size too small on the pump jets.

It will be done, all in good time,

Will

nomadtrash · Post by **nomadtrash** » Mon Nov 21, 2005 10:03 am

I ran at the Test-n-Tune on Friday night. The best I was able to get was a 9.29@74.5mph. That is around 14.5 in the quarter based on online calculators. It should have been a little faster but it was only 48 degrees outside. The tires and the track were very slippery. I was also having a lot of trouble shifting gears. My syncros are mostly gone. I estimate 1-2 tenths at each shift. If the track had been warmer and the tranny shifted well I would have been in the high 8's which equals to high 13's in the quarter.