1600tc engine

[selem]

hi every one,
me car is a 1978 fiat 131 1600tc 4 doors, current top speed 200km/h running with a dcnf 40 carb, using 4 2 1 exhaust manifold and a bit port and polish on a cylinder head. can you guy tell me how to make it faster maybe up to 220km/h or more. is it need a fast road cams and dcoe carbs.
your ideas are welcome and thank you very much.
selem.

[djape1977]

get a diff with longer ratio. from diesel preferably.
or bigger diameter wheels

[131R]

BIG turbo will do the job.  Then maybe good for 250km/h!

[bellamacchina]

You also can drive it on the TGV, saves fuel and you reach over 300!

[jasonh131]

AS the American's say 'you can't beat cubes' (or cc in euro terms)

[Tas131]

A basically stock, 30+ year old Fiat 1600 that indicates 200Kph road speed. I'd be looking for a more accurate speedo!

[mirafiori76]

Or is there a 1300 rear axle mounted? Just asking...

[djape1977]

yeah, that might be it!

[stathe174]

Why? What a rear axle from a 1300 has to do anything with the speedo?

[mirafiori76]

Have that axle under my Abarth replica together with tuned 2000 TC and Racing gearbox. Very fast acceleration, the revs go up, but top speed is 160.

[mirafiori76]

Speedo is mounted on gearbox. Every 131 has it's own speedo wich is in line with engine, gearbox and rear axle.

[stathe174]

I know that but he says that he reaches 200. So what effect a 1300 rear  should make?

[djape1977]

and number of teeth on speedo pinion in gearbox is matched to number of teeth on diff.
1,6 standard diff must have longer ratio than 1,3 diff so if you install 1,3 diff and leave 1,6 speedo pinion in the gearbox you'll get higher than real speedo reading for pecentage that 1,3 diff is shorter than 1,3 diff.
example:
standard lada 1,5 diff is 39/10
standard lada 1.2 diff is 43/10
diference between the two is roughly 10%
installing a 1,2 diff into 1,5 car will give 10% higher speedo reading, although real max speed will be 10% lower.
result - speedo is showing 200km/h and you're actually going 180.

[stathe174]

OK.Now I get it Thank you djape

[djape1977]

oh, one more thing: you'll need 10% more engine revs for same speed.
if original 131 1600 was capable of 180km/h on 6.000 revs, now it would need 6.600 for same speed.

i've had 43/10 diff in my fiat powered lada for a while and it would do max around 170km/h but on 7.000rpm

wheel size is also a factor
with bigger than standard wheels you get lower speedo reading than real speed ad vice versa