Drag Tips

[ramboteamjon]

I was at Crail last sunday and was hoping to be running atleast high 14s but the best I could run was a 15.2. Does anyone have any tips for my launching please to get my 60ft times down? like what rev to launch at and what are the best tyres for drag and daily driving?

spec:

kuhmo tyres
fully stripped interior
stock B16B
buddyclub racing spec condensor
NGK laser plugs
NGK blue leads
top fuel induction kit with 66mm cold air feed
Spoon 4-2-1 manifold
de-cat
2.5 custome exhaust system
Mfactory 4.9 Final Drive
Mfactory lightweight Flywheel
Spec stage 2 clutch
mapped with a P30 ecu on Crome (vtec is 5.2k to 9.2k)

Just wanted to know will my 4.9 final drive affect the performance of my car now that its been mapped and the rev limit is higher? when I think about it is the 4.9 final drive still of benefit?

 

[leeK9]

get yourself on a private strip of tarmac and practice practice practice

every car is different but to put it simples you want to take of without bogging down and without spinning needlessly

the grip levels should be felt by the driver and power feathered in accordingly

throw in the 2nd cog and foot to the floor

or try get a set of R888s to help

 

[oscarsayco]

Get yourself a set of slicks and traction bar and launch at 7 or 8 rpm another thing dont just dump the clutch let it slip.

 

[CR1S]

Oh I thought that was bad? haha
Thats to help traction I take it?

 

[Vtec6000]

Are you preloading the clutch before leaving the line? This helps a lot to reduce wheelspin and get off the line quick

 

[Ernie]

Post up your time slip or details from it, that will help us to help you.

You really should be ALOT quicker than that... the 4.9fd is ideal.

 

[CR1S]

Are you preloading the clutch before leaving the line? This helps a lot to reduce wheelspin and get off the line quick

What does that mean?

 

[Ernie]

You raise the clutch pedal so that its on the biting point of the clutch and hold the car on the handbrake to stop it pulling forward, this also help put less strain on the drivetrain when launching, so you dont snap driveshafts etc.

 

[cormy]

Post up your time slip or details from it, that will help us to help you.

You really should be ALOT quicker than that... the 4.9fd is ideal.

4.9 final drive isn't the best for dragging racing, it's more ideal for track racing. The 4.9 runs out at about 140 and then acceleration slows down. 4.7 is a good mix for both. This is from experience, I've had 4.4, 4.9 and now 4.7 and the 4.7 is the best

 

[CR1S]

You raise the clutch pedal so that its on the biting point of the clutch and hold the car on the handbrake to stop it pulling forward, this also help put less strain on the drivetrain when launching, so you dont snap driveshafts etc.

Ah thank you

 

[Ernie]

4.9 final drive isn't the best for dragging racing, it's more ideal for track racing. The 4.9 runs out at about 140 and then acceleration slows down. 4.7 is a good mix for both. This is from experience, I've had 4.4, 4.9 and now 4.7 and the 4.7 is the best

I disagree, you want to be at peak power in 4th crossing the line, on a b16 the 4.9 is perfect in a s4c box. I used the 4.7fd and lsd in a y21, which is very similar, crossing the line at 9k @ 107-109mph.

Who cares that it tops out at 140, your crossing the line at around 100mph!

This is using 205 50 15 tyres.

The b16 lacks the power to pull in 4th strongly, the shorter the ratio the better, aslong as you dont need to shift.

 

[ramboteamjon]

get yourself on a private strip of tarmac and practice practice practice

every car is different but to put it simples you want to take of without bogging down and without spinning needlessly

the grip levels should be felt by the driver and power feathered in accordingly

throw in the 2nd cog and foot to the floor

or try get a set of R888s to help

Thanks for the reply mate much appreciated! yea defo need to get mega practice in, there are some quieter thrash days coming up at crail so I will get along and play about and do exactly as you say! yea R888's are on my list of things to get!

Get yourself a set of slicks and traction bar and launch at 7 or 8 rpm another thing dont just dump the clutch let it slip.

Cheers for the advice mate, slicks for just drag would be sweet I will look into it! cool because I usually just launch at like 3k and I always dumped the clutch! thanks

Oh I thought that was bad? haha
Thats to help traction I take it?

yea I thought it would be bad too but so was the way I was doing it I suppose! lol

Are you preloading the clutch before leaving the line? This helps a lot to reduce wheelspin and get off the line quick

the clutch is fully in before I launch! no no I suppose? lol

Post up your time slip or details from it, that will help us to help you.

You really should be ALOT quicker than that... the 4.9fd is ideal.

Will do mate cheers!

Yea I was thinking I should be alot quiker and just wasnt sure if the 4.9fd was helping or not!

You raise the clutch pedal so that its on the biting point of the clutch and hold the car on the handbrake to stop it pulling forward, this also help put less strain on the drivetrain when launching, so you dont snap driveshafts etc.

Perfect thank you!!

4.9 final drive isn't the best for dragging racing, it's more ideal for track racing. The 4.9 runs out at about 140 and then acceleration slows down. 4.7 is a good mix for both. This is from experience, I've had 4.4, 4.9 and now 4.7 and the 4.7 is the best

Great advice thanks!

I disagree, you want to be at peak power in 4th crossing the line, on a b16 the 4.9 is perfect in a s4c box. I used the 4.7fd and lsd in a y21, which is very similar, crossing the line at 9k @ 107-109mph.

Who cares that it tops out at 140, your crossing the line at around 100mph!

This is using 205 50 15 tyres.

The b16 lacks the power to pull in 4th strongly, the shorter the ratio the better, aslong as you dont need to shift.

Yea this is why I bought the 4.9fd, I dont care for top end power at all, its 0-100 I am bothered about but its my 60ft times that are holding me back I think and need more practice!


Thanks again guys, rep added to all of you!

 

[Ernie]

What was your 60ft?

0.1 off yor 60ft equates to 0.2 off yor time on a clean run 0.3 off yor 60ft would give you 0.6 and so on... so thats where you can make lots of time... BUT on road tyres, even soft tyres like 888's you are limited, track tyres like 888's have very stiff sidewalls, stiffer than road tyres, so dropping the presure to give you a bigger contact area dosent really help as the tyre wont deform, 20psi is about as low as you can go, so your 60fts are never going to be the best (a 2.0 flat would be very good on road tyre). The other side to this, is I've found the b16 cant pull as well in 3rd and 4th with low tyre presures (15psi and below on suitable drag radials) so what you gain on the start from the larger contact area, you lose at the top end of the track. This was not the case with my old b18c6 engine, it could pull through the top end ok.

A way to get round this would be to use a smaller wheel tyre combo like I mentioned above, but I never got chance to test this theory. You may not be affected by the above as much as you have the 4.9fd, posting the breakdown times and mph of your slip will help to identfy the weak areas.

It takes a fair bit of dialing in to get the balance right.

 

[ramboteamjon]

What was your 60ft?

0.1 off yor 60ft equates to 0.2 off yor time on a clean run 0.3 off yor 60ft would give you 0.6 and so on... so thats where you can make lots of time... BUT on road tyres, even soft tyres like 888's you are limited, track tyres like 888's have very stiff sidewalls, stiffer than road tyres, so dropping the presure to give you a bigger contact area dosent really help as the tyre wont deform, 20psi is about as low as you can go, so your 60fts are never going to be the best (a 2.0 flat would be very good on road tyre). The other side to this, is I've found the b16 cant pull as well in 3rd and 4th with low tyre presures (15psi and below on suitable drag radials) so what you gain on the start from the larger contact area, you lose at the top end of the track. This was not the case with my old b18c6 engine, it could pull through the top end ok.

A way to get round this would be to use a smaller wheel tyre combo like I mentioned above, but I never got chance to test this theory. You may not be affected by the above as much as you have the 4.9fd, posting the breakdown times and mph of your slip will help to identfy the weak areas.

It takes a fair bit of dialing in to get the balance right.

Hey Ernie thanks again for your reply!

I will upload my time slip tonight so you can have a look but I am sure my 60ft times is very very poor!

I will take into account all you have said and see if i can get more practice and get the times down a bit! i would be over the moon with a 14.9 so i hope that is achievable!

Thanks again!
Rambo

 

[vti2010]

My old milno red ek4 ran it in 14.8 as said practice makes perfect

 

[Airwolf]

let me know the next time your heading up for Crail and ill come with?

 

[Ernie]

You should be aiming for a 13.9 not 14.9...

Uk record for a n/a b16 is 13.7 as far as I can find.... My son is building an EG at the moment we hope will knock 0.5 off that.

 

[ramboteamjon]

My old milno red ek4 ran it in 14.8 as said practice makes perfect

Thats a great time well done, if I could get that I would be well happy! Yea need way more practice!

let me know the next time your heading up for Crail and ill come with?

Will do mate!

You should be aiming for a 13.9 not 14.9...

Uk record for a n/a b16 is 13.7 as far as I can find.... My son is building an EG at the moment we hope will knock 0.5 off that.

a 13.9 I wish!!

in an EG you will do that no probs!! Good luck!

Thanks again for all info Ernie. Sorry been mega busy with work and stuff so not had time to post up sheet but will do this week!

 

[Colin_D13B]

You raise the clutch pedal so that its on the biting point of the clutch and hold the car on the handbrake to stop it pulling forward, this also help put less strain on the drivetrain when launching, so you dont snap driveshafts etc.

If you like your clutch i wouldnt be doing this
I leave it out from the floor
in an ek9 you really want to be launching around 7k
Toyo R888 medium compound!

Video of my friends ek9 vs DC2-R
http://youtu.be/aN1hOOIwLLM

 

[Airwolf]

Well clutch or driveshafts really