Help w/ 1/4 mi. Times

JC671

Fellas, I need your help. I'm running some pretty shitty times but let me explain all the details first then maybe you guys can chime in to exactly what's wrong.


First off, I'm at Guam where the track elevation is somewhere are 500ft. above sea level.

Secondly, the track is not prepped at all. The launch pad is bare concrete and sometimes they only laydown VHT on the right lane only. The road mixture here is made out of coral which makes it very slippery. Also, the humidity here can get to 100% easily. With that said, most people who run there cars here run about .5 to 1 second slower than those in the states with a good track.


They don't track 60ft times here which why it's so hard to determine how good/bad your launch is. My problem is that I ran my car bone stock, then later with the Ark type 2 cbe and dropped on H&Rs, then last night with my cbe and injen intake. I didn't see/get any real improvements at all even in the 1/8 or 1/4 mi times or mph.

Here my best bone stock run:

R/T: .6538
330: 6.2172
1/8: 9.3922
1/8 mph: 77.72
1/4: 14.3481
1/4 mph: 98.67

Best run with CBE and drop springs:

R/T: .4760
330: not recorded
1/8: 9.3899
1/8 mph: not recorded
1/4: 14.3489
1/4 mph: 99.34

Best run with injen cai, ark cbe & drop springs:

R/T: 1.1040
330: 6.2518
1/8: 9.4089
1/8 mph: 78.55
1/4: 14.3331
1/4 mph: 99.99


So here's my frustration. Why have I had my best run stock. I know traction is the issue big time because of track condition but shouldn't I at least see the difference in trap speeds with more mods added? I mean I'm launching at 2500-3000 rpm and shifting at 7500 not bouncing the limiter on any of these runs. What's wrong and why ain't I seeing a change of times or at least a mph difference other than 1mph on the quarter? Please help.. This is on stock sports wheel/tires BTW. Thanks.

m4a1mustang

A slight change in weather conditions could make a big difference on your trap speeds. That could explain the marginal difference before/after mods.

Given your 330' and 1/8th times I'm guessing your 60' times are in the 2.3-2.5 range.

How are you launching? Are you dumping the clutch from 2500-3000 RPM? If you are, try to slip it instead so you can manage the power you are putting down for less wheel slip on the launch... and practice, practice, practice!

500' above sea level isn't too bad, but given your humidity issues I think that you might be looking at low 100 mph traps on a good day. You very well could be running mid-13s in better conditions stateside, which is about average for a 6MT Z, but I have a feeling you should be running a high 13 or 14-flat if you can improve your launch.

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serturbo

Your mph is increasing with every mod and that shows an increase in hp, but it isn't where it should be. What temp is your engine at when you make your runs? 60 ft times would help us a lot in determining how well you are launching. Try to find someone with a Vbox. It will give you accurate 60 ft times. Don't use accelerometer based units because they can be messed up by wheel hop.

JC671

Your probably right about the 60ft. but you need to understand that there is no track prep at all. Everyone here needs slicks or DRs in order to get off the line the right way here.

As far as technique I'm dumping the clutch but feathering the gas till it grabs in first.... I have cut constant 1.8 60ft. On street tires with my 91 turbo mr2 back in Sacramento Raceway California and steady 1.5-1.6 on slicks with my turbo RSX type S that ran 11.2 so I know it's not that big of a learning curve as I'm not green tonthe track..



My problem is why ain't i seeing the difference in mph trap even with shitty launches? Shouldn't i I see a difference in time at all? What gives?

cfweber

seat of your pants:does it feel quicker/stronger after the improvements/mods?

can you find a good surface anywhere and does it seem faster there?

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m4a1mustang

The Injens really aren't going to give you much gain at all. There is only a small power gain at peak (over the last 500 rpm or so) and I'm not quite sure what the ARK exhaust does in terms of power gains.

You picked up about 1.5 MPH from stock, which, given your weather conditions, is probably average.

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LostMarine

if your spinning tires even after the 60', its going to hurt mph. you may not be spinning the tires enough to feel it during the run, but slippage adds up. but like said before, conditions can effect 1-3mph depending.

remember, not every track day is going to be the "best"

JC671

It does feel notably faster especially after the CBE upgrade that's for sure. As far as better road, that's just how Guam is. There are few roads that are black Tarmac here...


The CBE average dyno gains are posted on the Ark group bu area. Dyno proven to increase whp by 20whp.



True and I understand that weather does affect it alot but I should be able to see gains somewhere. I'm trying to upload my best run last night so you guys can see how terrible the track is and how bad I'm spinning as their are two different surfaces on the track.

chuckd05

Next time try to just ease off and floor it with out any dumping at all. Like a feather from 1200-1500 tops. Just get it rolling than hit it. That should net you a 2.1-2.2 see if it's any better. Than find a middle spot between what you've done and that.

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09 370Z 6M PW - FBO Best 1/4 mile = 12.926 @ 109 SOLD -- 08 BMW 135i - FBO 12.1@120mph SOLD -- white 09 e92 335 Coupe Mtech - 11.9 @ 119 :-)

JC671

So here's my best run last night. That annoying sound In the background is not my car but an 12 sec atv quad.



Please let me know your opinion.... I have a feeling everyone will say just get slicks or dr's and run the same mods again which I will be doing...


http://i27.photobucket.com/albums/c1...z/768f8177.mp4

chuckd05

you spun way too much off the line.. prob starting from too high of an rpm for your technique you are using... and try to shift a little faster...

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09 370Z 6M PW - FBO Best 1/4 mile = 12.926 @ 109 SOLD -- 08 BMW 135i - FBO 12.1@120mph SOLD -- white 09 e92 335 Coupe Mtech - 11.9 @ 119 :-)

JC671

Indeed I spin off the line alot but any lower rpm would cause the car to bog. We all know that there is a delay with our cars when you hit the gas at WOT then the car responds a bit slow.

As you can see it's coral/bare concrete mix.

I'll launch at 2000 rpm next with the same technique or keep the same rpm and feather the clutch.. As far as shifting, where do you get from the video that I'm shifting slow?


How does the final drive gear work the higher the number the shorter your gearing is? And the lower the number the longer it is? What's the stock final drive gear for the Z? How much of a difference has that affected your 1/4 mile time?

destinyZ

do what i did:

headers/tps or hfc/cbe and i was hitting 14.1-14.01 was my best

i hear your z was running better times then a twin turbo z....i think you did great

found the problem but we can talk about that somewhere else...

chuckd05

Higher gear number the shorter the gears...

Def helps the 1/4 mile time but I haven't been to the strip with the 4.08 FD yet.

Stock is 3.73? Something around 3.7

__________________
09 370Z 6M PW - FBO Best 1/4 mile = 12.926 @ 109 SOLD -- 08 BMW 135i - FBO 12.1@120mph SOLD -- white 09 e92 335 Coupe Mtech - 11.9 @ 119 :-)

m4a1mustang

Final drive on the manual cars is 3.69.

Of course a 4.08 gear swap won't do you any good unless you have traction.

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