The Car is Born and living in Derby

[plopabiggi]

Hello to everyone,

you dont know how welcome it is to find people who know cobras. I am not a builder, but took the short cut. I own the Cobra that was built on "a car is born". I have owned this car for a few months and had some problems - which i have nearly sorted.
The heater matrix leaked, then the petrol tank leaked, then the clutch cable snapped and the frame to the alternator gave up. At this point i felt i had had enough. Anyway still with it.:thumb:
I am hoping that some of you guys can help me out with the remaining questions and minor problems. I have read through a lot of the threads and have already learnt a lot after just 2 hours.
As you may know my cobra is sierra based and running a 1.6 litre diff. The engine will spin the rear wheels very easily and snake without much pushing. This leads me to, which has come up on the forum before, what type of better suited diff (LSD) can i get. Driving in the wet - both on the road and front seat - can be very off putting. I contacted Quaife, who make diffs ,said that they do not do diffs to suit the sierra un less i wanted 10.(err no!).
The next question, sorry if this is a stupid question, On track the best top speed is 110 mph in fith gear(approx 4000 revs). Is this correct. I was expecting a car like this with 5.7 litres to be able to break the sound barrier.
I will be changing my tyres as they seam to be a problem according to your forum.
All the best and hope to hear from you soon.
ps. sorry if that was a bit of a mouth full for openers

[Purple AK]

Hi Plop.

Welcome to the Mad House :thumb: I'm not a Pilgrin owner, But the 1.6 Sierra diff cant be doing you any favours, supprised it's lasted this long! The Sierra Cossy Lsd is the way to go, although it may involve changing the drive shafts etc. Have a look here http://www.donorspares.co.uk/uprightshubsandaxles.htm

[kevchard]

Welcome to the funny farm, I have to say I have watched your car being built a few times, good luck with it.
Cheers
Kevin

[bruce h]

Hello
Re your diff Might sound silly but have you spoke to pilgrim ? they are normally quite helpfull
Can you enlighten me on the tyre problem?
Thanks Bruce

[plopabiggi]

Hi Bruce,
thanks for your reply.
The tyres i have are the General XP and are very skiddy in the wet. A previous post suggested that this was the case with these tyres. I hope to enlarge my wheels and have wider low profile rubber. I hope this coupled with a better diff will improve road holding when entering turns. I have spoken to Pilgrim,but, they did not give any advice on top speed (Why do you want to go faster than 70mph When the limit on the road is 70 mph!) or a better diff solution.

[plopabiggi]

Originally Posted by kevchard

Welcome to the funny farm, I have to say I have watched your car being built a few times, good luck with it.
Cheers
Kevin

Thanks Kevin.

[TINKA]

Just my 4 pence worth, but with such a light car if you make the rubber on the back even wider then it will only make things worse in the wet although in the dry that is another story :thumb:

[plopabiggi]

Originally Posted by TINKA

Just my 4 pence worth, but with such a light car if you make the rubber on the back even wider then it will only make things worse in the wet although in the dry that is another story :thumb:

Hi Tinka,
is the right way to with the cosworth diff and drive shaft and keep the tyres the same. Will the diff improve the top speed or is that my lot.
Adrian

[TINKA]

Hi Adrian, not sure what the ratio is on the cosworth diff but it is passably a bit stronger. What you really need is to look at the diff ratio, with the Jag diffs most people go for the 3.54 ratio for acceleration or 3.31 if you are going to do more touring ( although it either are fine ) I have a 3.31 and although I am replacing the RV8 at the moment was never able to achieve full speed due to the lack of aerodynamics, with the higher ratio you will achieve a greater top speed but it will mean higher revs when cruising and so using more fuel. As for Tyre size I would normally say stick with what the manufacturer recommends or if you do want bigger tyres don't go mad as you might find it is actually detrimental to the handling of your car which is not what you are after. Lower profile tyres will improve your road handling but be aware that this sometimes comes with a harsher ride.

Hopefully we will see you at one of our meets in the near future, if you would like details let me know your Email address and I will forward some . :thumb:

Cheers

[Miket]

Originally Posted by plopabiggi

Hi Tinka,
is the right way to with the cosworth diff and drive shaft and keep the tyres the same. Will the diff improve the top speed or is that my lot.
Adrian

Keep the tyre sizes the same, but you must get some decent rubber on the car, I had General XP's on the rear of my Sumo, they are god dam damgerous.