Iwanna928

Well it looks like I will be going to the drag strip on sunday. They have a runday sunday race and grudge day at Bradenton.

I was wondering who has taken their car to the strip and what tecnique they used off the line.

Tire pressure, rpm etc. I have street tires, BF Goodrich g-force sport 255/40/17s. Don't think a burnout will help.

Let's see how she does w/ the exhaust done and hazy syncro's. This will give me a baseline for after I install the euro cams to see what and if the difference is.

Dyno sheets are one thing, how she pulls one the track is a real indicator of what type of power she is making.

Any thoughts and I would love to have some company. Anyone feeling like beating up on their Porsche!

Stephen

LUCKYJACKASS

Sounds like a lot of fun. Is that this weekend? If so, that sucks, I will be in St Pete next Friday (23rd) for a week. I would like to see what kind of times you would get. Don't have either of my P-cars in Florida, but would take my Ranchero out there just for kicks. Ever go to Sunshine Speedway (or is the strip still open)?

Iwanna928

That's to bad. It should be a lot of fun. Sunshine is alive and well but is 1/8th mile and I want to see what it will do in the 1/4 mile.

Not sure if 14's are possible with a 79 and bad syncro's so I am thinking low to mid 15's.

Stephen

inactiveuser1

I always stay out of the water burnout area as the water in the tire treads will drip down under your tire when sitting at the line and cause you to spin more when running a street tire.If you have to do a burnout you would be better going around the water and back up into the top part of the burnout area where it is just alittle wet don't back into the water all the way and do the burnout there.
Even mostly stock with 2.20 gears and AT car going in the water mine will spin so I do the above or just plain stay out of the water do not drive thru it just go around it.

IcemanG17

Since all 928's have a wide powerband....you don't need a "perfect" launch to get good times.....in my S4 automatic I just floored it and went...shifter in "D"...pulled a 14.55.....

I have heard manual 928's are a bit prone to axle hop...so be careful....but all of mine burnout quite nicely!!

I think a well running OB 5 speed is a 15 second car...maybe high 14's if you get it lighter with a great launch!

atb

I think with the 5 speed cars it's important not to put to much emphasis on timing and trying to get the perfect launch. Just get the car underway consistently and let the motor do the work. Stalling the car or lighting up the tires just isn't going to do you any good. Once you are underway, accept the fact that a fast shift isn't going to win you the race, and take your time with solid, clean shifts. I think a sub-15 in an OB is asking alot, but Brian may be right in that a perfect launch may get your there. Good luck and have fun!

inactiveuser1

Brian,
what 1/8mile times did it run when you ran the 1/4?
Did it show the 660 foot time?

IcemanG17

http://www.dragtimes.com/Porsche-928-Timeslip-5435.html

60 ft of 2.230 or SLOW..... as we all know 928's are not exactly fast right off the line....

atb

Here are some E/T's for a quartermile from our local group (from long ago).

I think I may still have the slips stored somewhere with all the specs, I'll see if I can dig them out.

http://www.tower-mt.com/PacNW928/eve...625-Drags.html

http://www.tower-mt.com/PacNW928/eve...-Drags-II.html

inactiveuser1

Our 60 ft times are within .01 and the 1/8 mile is very close also.
660 ft (1/8th mile) times are close also.
Still haven't ran it with the new Cold Air Intake
Was hoping it would drop into the high 9.30's in the 1/8th.
http://www.dragtimes.com/Porsche-928...lip-16213.html
http://www.dragtimes.com/1987-Porsch...ecs-16213.html
That was before the Cold Air intake 9.43 to 9.49 area.
Hope to get to the track by the end of the month weather permitting.
I see another 928 running in the 9.17 to 9.20's with a blue flame exhaust not sure if he is on the list?
Car is at:
http://www.dragtimes.com/Porsche-928...lip-13358.html
Exhaust looked nice at:
http://www.blueflameperformance.com/...id=80&pageid=3
Brian and Adam,thanks for posting ET.

ptuomov

If you are interested in a reliable measure of engine power that is largely independent of other changes such as tires and suspension, the 1/4 mile trap speed is it. ET is determined by a combination of traction and power, the trap speed mostly just by power.

RKD in OKC

When I was doing intercooler testing at a 1/4 mile strip with my 944 Turbo for Lindsay Racing I tried to be as consistent as possible. All the veteran drag racers at the test and tune night told me I was so consistent I would win doing dial in. I did two runs with each of three intercoolers. The two times for each intercooler was within .001 of each other.

I went around the water and did not do burn out because I was on street tires.

I revved it to 4000 and just dumped the clutch on the light and floored it. 4000 was was enough that it wouldn't stall dumping the clutch and didn't get any spin. It wasn't pretty though because it wheel hopped the first 40 feet, every time. My reaction times were pretty consistent from .004 to .006. I think that is good because my reaction time was way faster than anyone I went against.

I watched the tach and shifted just as the needle passed 6000, again trying to be as consistent as possible. I did beat every car they put me against except the last one. It was a Camaro with a blower stack sticking up out of the hood, big fat racing slicks on the back and those little skinny tires on the front.

The idea was not to get the fastest time, but to be consistent so we could compare the differences the intercoolers made. The first one was stock. The second one had one end connection opened and would replace the stock with no modifications. The third one had both end connections modified and required modificaton to one of the intercooler mounts. The second was 1/2 second faster than stock, and the third was 1/2 second faster than the second.

Lindsey Racing had asked me to do the drag strip testing because we did the same thing on a dyno and it didn't show any power gains. They wanted to do the drag strip thing because they felt the dyno didn't represent the power gains because you can't really get any fresh air thru and intercooler sitting on the dyno. Seems they were right.

atb

You've got to be careful about this kind of analysis with the 2.20 geared A/T's, I think their trap speeds are misleadingly low because they hit the rev limiter right before finish line and you are forced to choose between hitting against the rev limiter while crossing the line, or shifting into third for about half a second. With the shark tuner, it would be interesting to raise rev limit an extra few hundred rpms and see what happens to the trap speeds.

Iwanna928

I am going to the local vacant parking lot and try some launches before I hit the track. I will try dumping the clutch at different rpm's and see what works best.

Then I will try slipping the clutch, launching the car at a high rpm but not engaging the clutch completly. Tough on the clutch as it gets hot but might end up with a better launch.

I will make a bunch of passes, as many as I can within reason. If slipping it launches best I will start with that and after that I will probably just dump it at said rpm as I don't feel like burning up my clutch with slipping it all the time.

Also will be interesting to see how much of a time difference there is, that is of course if my reaction times aren't all over the place!

Stephen

Imo000

don't bother with the parking lot. The track conditions are way different that a parking lot. For me, dumping the clutch at 2500rpms was the sweet spot. just enough wheel spin to get a 1.9sec 60ft and not too much to get out of hand. Pulled dozens of high 12sec passes like this. Before the SC, and depending how much traction compound they laid down the track, I had to go 4000 rpms and sometimes higher. This was all on standard size street tires. And stay out of the water box.