refresh951

Sending you an email.

pole position

It's hard to tell from the video but it appears that you do not launch the car , like dropping the clutch or feathering it thru higher rpm's while you take off, sounds and looks like a regular traffic stop start. You are also granny shifting.

Btw, I attempt to constructive criticize you , not bashing

refresh951

lol, no worries. This take off was pretty soft (I launched harder is some other runs) but a "regular traffic light stop start"? Come on now

blown 944

From my experience, his shifts (at least 2nd, and probably 3rd with that trans,) are probably necesssry. If I try to hit the shifts hard it will get sideways. I can lose a lot of et from it.

The launch is definitely too low and is probably losing at least .4 seconds on the overall.

However, I really think that the s2 trans is not the best for this kind of power. I find that being in the meat of the torque is what works on these combos. His gets through the rpms quickly, but doesn't seem to pull the mph with it.

For example, sometimes I'll run mine just through 3rd and still trap over 120 shutting down. If I get into 4th for any time period (which is what's happening at a high 120 trap) the car just pulls like a freight train.

IMO the s2 trans for this power level is only good for congested city driving and maybe a small auto x.


I'm betting that with a std turbo trans, you would have trapped very close to me. ET, on the other hand would need you to be more aggressive on the start and have some sticky tires.

refresh951

I did try being more aggressive and things got worse, especially in 3rd.

Once last night I hit 4th just right and it felt like a sling shot. Very addictive experience.

I love it for mountain runs but even in autoX it is not ideal with the torque I have.

refresh951

From my daughters phone

blitz951

Blown944's analysis is right on especially that regarding the s2 tranny.

333pg333

Didn't seem too bad to me? In terms of a half decent launch and shifting. Also didn't notice any real wheel spin but I think I agree about the shorter gearing maybe hurting for this application.

What rubber were you on Shawn?

User 52121

LOL your car rips through 3rd faster than mine rips through 2nd when it's *not* misfiring!

refresh951

Thanks Pat. If you watch closely you can see and hear (rpm) spin in the lower gears. This was with lower boost and letting off a bit in 3rd which was necessary. Car does not go sideways with wheel spin but stays perfectly straight.

Tires are Toyo Proxes R1R's

NZ951

Mate with that trap speed you should be in the low 12's or high 11's. What's the 60 foot time? Must be mid 2's? Im sure there is a high 1 in it.

I think its actually hard to shift these cars quickly because of the linkage and the boxes willingness to get in (I dont have the answer only guessing). It can be done though.

333pg333

The thing I always like is knowing there is more to be had for the next time I go to the track. I don't know much about dragging but I'm sure it's the same in that regard. You will get the e/t's down and trap speed up in no time Shawn. Great starting point!

I was looking through some old data and came across accel times on the racetrack. We don't know what our 1/4 mile times would be until / if we try it but I found coming out of a slow hairpin bend and going uphill we did a 100kmh to 150kmh in 2 seconds. That's 62mph to 93mph. We did 62mph to 124mph (100k-200kmh) in 6 seconds in the same uphill stretch which obviously involved a gearchange. Not sure if the slow hairpin hurt us more than a standing start would? Also managed a 200kmh / 124mph to 250kmh / 155 mph in 5.7 secs. This was from some months ago and I'm sure we'd be quicker now. Do you guys have logs of similar in gear acceleration times?

blown 944

Duke did a calculation awhile back in my thread i think. That was when I trapped 124.

I'll be borrowing a vbox soon. Maybe this week.

I think Shawn has a lot of room for improvements. Which I also like

refresh951

Great input. I will be going back in September with a turbo tranny, an EBC controllable by gear, and hopefully a little more experience.

Tom M'Guinn

Great results I'd say -- congrats! Trap speed shows the power and plenty of it. Losing traction in 3rd is impressive too! If I can help with the Arduino boost controller let me know. I've had that project on the back burner too... Mac valves are easy to control and cheap. Also see my speedometer calibrator in the link below for details on reading the speedo signal. With it and the tach signal you can calculate the gear you're in and adjust boost accordingly...