Tintop & Cabby weight difference

probally one for dubboy so whats the weight of a 76 tintop and a 88 cab ?

just want to see how much weight i need to loose for the next track run

dub76 tintop 20v did 14.1
my cabby     20v did 14.6

is it down to the weight ? just couldnt keep up with him  :cry:

about 100kg. more i think for clipper kits. you could have the same weight and still lose. assuming all is equal apart from the floppy bit (i.e. engine, eight, driver etc…), you would still lose. it's just the aerodynamics. a proper roof will always cause less drag than a floppy one.
 it's still a very good time ben. if you want to reduce times into the 13's, i'd look more towards the diff and maybe gearing, rather than the engine

wooders at last you talking sense

the gearbox ratios are an issue my 1st and 2nd are spot on but my 3rd and 4th need 16v ratios i reckon

going to get some slick tyres for the next trip

as for the roof its shrunk so much the air gets inside it and causes it to ballon

so new roof
slicks
gearbox rebuild

if youre wanting 2 shave 10ths then try taping up all the gaps between the pannels etc! may work may not but ive seen a few supras n skylines doing it! also race without the bonnet on if they'll let you!

Tape up the gaps sounds interesting, but why remove the bonnet?  Won't that have the opposite effect to the tape theory,  or am i missing something (probably) :?

weight reduction. ive seen it done before but not sure what the effects on the drag are.

el_sicko said

weight reduction. ive seen it done before but not sure what the effects on the drag are.

There's a direct relationship - up until air resistance becomes significant, which is probably around 100mph+. Ie every 1% weight loss, will give 1% better ET. Ben, you're a bit stuck with what you can remove if you're driving the car to-from, but you could leave this at home:

4x Door panels (but refit the winder handles)
Handles
Fittings for mirror internal adjustment
Rear seat
Parcel shelf
Speakers (probably in door cards?)
Stereo
Carpet
Underfelt soundproofing material
Handbrake trim surround
Gear lever gaiter

And then once at the event, remove these too:

Wing mirrors
Rear bumper
Passenger seat

Also do this:

Decrease front tyre pressures to 22psi
Increase rear tyre pressures to 40psi

don't know how practical it is, but i wonder what improvements you would get from creating a smooth undertray. I can imagine the spare wheel well and rear lower panel aren't very good for are flow.

emm said

don't know how practical it is, but i wonder what improvements you would get from creating a smooth undertray. I can imagine the spare wheel well and rear lower panel aren't very good for are flow.

I'd say, not worth the hassle. It would be far easier to simply lower the car once you're at the event, with a GTI chin spoiler, you're going to prevent a lot of the air going underneath the car once its lowered 80mm or so.

good advice yet again paul im looking at the gearbox ratios i think my 1st and 2nd are spot on for the strip but 3rd gear is where i start to loose time

going to look at maybe getting a 16v box and using the 8v 1st and 2nd
also slicks on the front if i can find some

i think i can also run a higher boost level for just 1/4 mile but would need to have major cool down periods before each run

but all said and done between mine and deans car the only difference is the weight and roof on the times i think

Yeah your prob right,  I see the new clio 192 has one and apparently its worth while,  but its not 1" off the ground!!  Having said that its always interesting to see people try to improve air flow but never think about the messy underside of a car.  I would probably say its as worth while are removing the handbrake cover.    But a lot more hassle

emm said

I would probably say its as worth while are removing the handbrake cover.

You need to remove that, to remove the carpet. No point putting it back in, chuck it into the crate of other parts!

Not saying I am obsessed with weight, but I noticed a 1" long sliver of insulation tape stuck to the floor, on Sunday, so I removed that too!

Lol  

Did you have All Bran in the morning as well?  No point in carrying anything inside!!

pauls car is anerexic plus he had rice crispies for brekky

going to t-cut the car later may loose a few pounds there

i should have gone to the loo earlier yesterday reckon that 5lb dump was lowered my times

deans best time was in rage after being hit in the pit lane  

bens_cab said

probally one for dubboy so whats the weight of a 76 tintop and a 88 cab ?

just want to see how much weight i need to loose for the next track run

dub76 tintop 20v did 14.1
my cabby     20v did 14.6

is it down to the weight ? just couldnt keep up with him  :cry:

Difficult to say with modified cars. The early cars are very light, you are looking at 750 kg for a small block. Big block cabs are around 940 kg.

well guys not feeling to bad now just been testing the my boost valve and it seems it doesnt hold boost like it should

the actuator was set at 7psi and the bleed valve adjusted to 14psi but when under load in 3rd the boost was dropping off to 7psi

just removed said item and adjusted wastegate to 14psi and it holds it now through every gear

typical i didnt see that yesterday but i had tunnel vision on the strip wasnt watching the boost gauge

Both the mk1 cab and tin top are about as aero dynamic as a house brick , Aero dynamics do obviously help but if you go for out and out power and correct gearing for power runs and lighten the car slightly, i cant see that it will be such a major factor, especially as you will be stripping against cars with simmilar aero dynamics and body shape

so what times did we get then gentlemen!!!!!!!??????

dub76 14.1 consistant
paul_c 14.4 consistant
bens_cab 14.6 not consistant

found a boost leak on mine so hope to do better next time

roof up or down ben?

some do say theyre cars are quicker with it down, dunno meself!


i think for your first outin in the cab thats pretty damn good, youll get 13s next time.