Technical Drag Racing Modifications

[g.mcdonald]

Hi, Just ran my 899cc cinq down a drag strip last weekend and got a best of 21 seconds.Hoping to improve the car to see max you can get out of a 899cc pushrod engine.Have striped most of the interior.So feel free to offer any sugestions.Want to see what can be achived with this set up before moving to a 1242cc.
Whats best way to lock diff (Wont be used on road)Dont like the idea of welding up the gears.
What are the widest steel 13" wheels that will bolt on to front and off what Fiat model.I intend getting slicks to try out.
Whats the best way to get tar sound proofing off the inside floor.
If i fit a bigger throttle body would the Ecu be able to reset with the engine running at tick over or would the car have to be driven on road. (car not on insurance anymore,and next drag race on sunday).
Thanks Graham

 

[craigb244]

diff would have to be welded really. or take it to a engineering shop and get them to make something (like a steel cube with 2 splined holes and another hole for the pin to go through. bit over the top)
cant help with the steels. I think all steel 13s are thin... maybe get a set banded?
the throttle body should be OK. the ecu needs to be driven to self tune. but on a drag strip the car is as full throttle and full load all the time so is not on part of the range the ecu can "learn" anyway.

 

[craigb244]

oh and the tar can be removed with a heat gun and scraper. clean it up with turpentine
horrid messy job

 

[g.mcdonald]

oh and the tar can be removed with a heat gun and scraper. clean it up with turpentine
horrid messy job

Thanks craig,have heard welding diffs not really the way to go as it weakens the metal,but might be worth a try on a spare diff.Have a 32mm throttle on there at the moment and it works fine and was going to fit a 38mm that i have,trouble is now that its off the road and trailered to the events,its hard to test out any improvements made.

 

[Brooky]

Why do you want to keep 13's?

I'd say turbo it, one did a mid 13sec a while ago, and thats without a LSD.
I have a spare LSD if you want to splash some cash

 

[rallycinq]

To remove the tar, wait till its really cold and chisel it off.

Cheers

D

 

[g.mcdonald]

Why do you want to keep 13's?

I'd say turbo it, one did a mid 13sec a while ago, and thats without a LSD.
I have a spare LSD if you want to splash some cash

Want to keep it looking a standard as possible so 13" steels,but a bit wider than standard,wouldn`t attract too much attention for that sleeper look.
I`ll keep you in mind for the limited slip diff,will it fit the 899cc box and what sort of money.

 

[bludvl_x19]

To remove the tar, wait till its really cold and chisel it off.

Cheers

D

A trick I heard of the other day is you get dry ice and freeze the stuff off. Dunno where you would get it from over there though

 

[rallycinq]

A trick I heard of the other day is you get dry ice and freeze the stuff off. Dunno where you would get it from over there though

CO2 Fire extinguisher contains 'Dry Ice'

Cheers

D

 

[ycming]

CO2 Fire extinguisher contains 'Dry Ice'

Cheers

D

hmm you sell those in ur shop !!!!

 

[rallycinq]

hmm you sell those in ur shop !!!!

Nope, sorry

Cheers

D

 

[jimbro1000]

Your best option for gaining speed is to shed as much weight as possible (I'm sure you've already worked this out) and reduce tyre drag so skinny wheels at the back pumped up hard. With 45bhp you aren't going to fry the front tyres too much especially on a proper drag strip with lots of rubber laid down by other cars. Grip isn't your main issue at this point - reducing mechanical losses to maximise delivery is far more relevant.

Be careful with the induction system too - you are better off fitting a panel filter in the original housing rather than an open throttle body or a cone filter as the resonator on the original system works rather well. If you go for a larger throttle body this theory goes out the window as the resonator is tuned to the original throttle body.

The final trick is practising your starts - the best results come from holding revs at *about* (depends on the engine) 4000rpm and dumping the clutch. Your aim is to get about 5% wheel spin to achieve maximum launch grip and avoid the engine bogging down. Too much spin and you'll waste lots of time.