My first time at drag competition (but questions)
 

Yesterday I was at my first drag competition with my FD. I was put in an open class and WON ! :cool:

My best run was 13.4 @ 106mph on 3 years old SP9000 tires. I was running 13psi.

Is the trap speed aproximately correct for my mods ? I thought I could go below 13secs I'm getting more and more this feeling that I'm loosing some HP somewhere (should be around 350hp with the mods in sig, no ?).

On my 14.22 run I had trap speed of 102mph.

Any comments, suggestions ?

I'm running 9/7 plugs and have a small exhaust leak at where downpipe mounts to the turbos. I have 3" downpipe and from the downpipc back, there is a probably 2" exhaust (in bad shape, need new one) till the muffler. I get full boost at around 2500RPM and it holds steady boost up until redline (and past). Sometimes at transition my boost falls down below 8psi, but picks back up to set boost normally.

MAHA LPS dyno showed 285hp at flywheel at 12psi, but that was with old plugs. New plugs made the situation better, butt dyno says quite some hp at top, but probably that still didnt get me much over 300hp.

What should I start to look at ? Could it be that the turbos are bad? There is some sprayed oil in IC pipes...

Please chip in ;)

Please post your time slips? We need to see you 60' times.

It could be because of your takeoffs, those are a big part of having a good run.

They didnt measure 60' times (its not a dragstip, just a competition). But if its worth anything, on my 13.4run I managed to get away from twin-engined suzuki swift (thus 4x4) with hugeass NOS.

They didnt measure 60' times (its not a dragstip, just a competition). But if its worth anything, on my 13.4run I managed to get away from twin-engined suzuki swift (thus 4x4) with hugeass NOS.

They didnt measure 60' times (its not a dragstip, just a competition). But if its worth anything, on my 13.4run I managed to get away from twin-engined suzuki swift (thus 4x4) with hugeass NOS.

Whooops... tripple post, sorry.

Your mods sounds very similar to mine (see sig). And our times are fairly close as well. My trap was a little higher than yours, which would explain why my time was a little lower than yours. I'd say you're probably right on track with where you should be. The trickiest part of the whole thing is launching, which your 3 year old tires probably didn't help much.

doesnt sound too bad for what you have.

Could be, but still I find ppl on the forum claiming 13.0sec for 1/4mile pass at 8-9psi and such. I thought I would be able to mid to high 12's.

And stock RX7 is said to run about 13.7. So my supposedly about 300whp rx7 would run only 13.4 ? Too bad I dont have an 60'ET reading to determine my traction.

Btw. here's the video where I win against a twin-engined, NOS charged swift:

http://www.mobisux.com/album/data/50..._rx7_swift.WMV

My start looks slow. Maybe its really old tires taking their toll. I droppped the clutch at 3k RPM and let the tires spin a bit (you can see me going sideways a bit for a moment).

911GT2, I'm still confused where about 50hp is lost compared to others with similar mods.

Could be, but still I find ppl on the forum claiming 13.0sec for 1/4mile pass at 8-9psi and such. I thought I would be able to mid to high 12's.

And stock RX7 is said to run about 13.7. So my supposedly about 300whp rx7 would run only 13.4 ? Too bad I dont have an 60'ET reading to determine my traction.

Btw. here's the video where I win against a twin-engined, NOS charged swift:

http://www.mobisux.com/album/data/50..._rx7_swift.WMV

My start looks slow. Maybe its really old tires taking their toll. I droppped the clutch at 3k RPM and let the tires spin a bit (you can see me going sideways a bit for a moment).

Dude...the problem with your ET is the track you were running on. That looks like a regular street. If you got sideways dumping at 3K, you aren't getting any better traction then you would on regular pavement. Go to a decently prepped track, and you will bog the hell out of the engine dumping at 3k. I had to dump at like 4-4.5k to get a decent amount of spin when I went to the track. The last time I went I was totally stock and ran a 13.8 at 100.24 mph. That was with a 2.02 60' time, which I thought was decent considering I was totally stock and had 225 street tires on the car.

IT WAS a regular road (with not the best traction). So with some good rubber I could even go into 12's ?

I'm still bothered with low hp reading though :p:

well i've never heard of that kind of dyno. i'd expect around 310 to the ground @ ~12 psi with your setup too. who knows, it could be just a really low dyno but then i'm not sure what your trap speed equates to.

...got a dyno sheet?

What trap speed would be "average or normal" for FD with over 300rwhp ?

Now I'm thinking - my Autometer boost gauge shows 16" of vacuum at idle. I read it should be around 18" with stock engine porting. Maybe my boost gauge is 2" off and maybe I'm running 2lbs of boost too low. That could maybe explain some of the HP lost...

Here is the dyno (hp recalculated to flywheel, 285hp / 260lb/ft tq (352Nm)):
http://www.viki-sp.si/private/dynochart1.JPG

And my EGT graph (measured at the tailpipe, but I have free flowing exhaust) says 570F at 2700RPM, 750F at 4100RPM, 930F at 5250RPM and 1110F at 6500RPM.

Is that a bit low, indicating rich mixture of AF ? I read on teamfc forum that Autometer themselves admit to 1-3psi of inaccuracy on their boost gauges which is alarming - my Autometer boost gauge shows 10psi at 2500RPM already, which is a little soon for old stock twins.

Opinions ?

Thanks!!

the low EGT temps are due to the temp being read at the tailpipe. thats alot of room for exhuast to cool down somewhat.. you need to have a bung fitted no more then 10 inchs from the block to get reliable readings.

^

Remove your restrictor, port your wg, and go 112+ mph

Having a 2" exhaust from the downpipe to the muffler, then that is a pretty big bottle neck. You will get some more power with a less restrictive exhaust, but I think your biggest problem really was the launch. 13.7 stock FD is the very best traction on the very best day, with the very best driver. Your car ran about what it should with a less than professional driver, on a shitty surface. If you want to see 12 sec ETs, then get some GOOD tires, go to a GOOD track that has been around for a while, where they spray down VHT, and either practice your launching or put a really good driver in the car.
I've only drag raced on a real track once (as that's not really my thing), and I ran a 13.3 at 107. I was launching like a pussy and pulling 2.2-2.4 60' times because I had worn out diff bushings, and was 3 hours from home (didn't want to blow my diff). Had I launched hard with a solid rear end, I would have been faster. Instead, I enjoyed what I ran, and drove home (as opposed to being towed home). Just be happy that you won, get some good tires, and work on your launches.

So how much time is lost on the street with normal tires (not new ones) compared to a dragstrip (lets say piloted by a pro) ? 0.5-1sec ?

I really wouldn't know, as I'm not too into drag racing. By "get new tires," I didn't so much mean that your tires were too old, as I meant to get some different tires. If you are all about dragging the car, then get some drag radials. If you are crazy serious about getting some sick times, then by a couple of ET streets.

Nah, my FD is my weekend car. Its by no means a drag car, but maybe I was just mislead by the times on the forum. I also enjoy my car at the track (with corners :p: )

I'm getting new exhaust and I will also check with some other gauge my boost if boost gauge is off.

If you can make it over to the UK there is a drag competition on at the end of May. Being Rotorstock it will have a good selection of FDs so you can see how your car relates to other similar cars. Your terminal speed does look pretty low, couldn't guess why as I saw 105 with just a street port and PFC(0.7bar) on road tyres (34psi).

It is impossible to say how much time you are losing by running your current tyres without having a 60' time. At the very least you should drop the rear pressures well below what you run on the street to maximise what you have got.

FWIW I gained almost 40rwhp by putting my car on a different dyno from a MAHA one 224->260 again at 0.7bar.