Acceleration of a standard 400

[4535jacks]

I bought a standard chim 400 as I've always loved TVR's. I also wanted a car that could accelerate 0-60 in around 5 seconds (I know many will post arguing that this isn't important). Recently I decided to test the 0-60 time and was horrified to find repeatedly that I could not get below 6.8 secs. This to me seems too slow for this car and engine. So either my technique is rubbish or i have a poorly chim.
I know the performance claims by TVR are unrealistic, but i would still expect the car to get to 60 in around 5.3 to 5.5 secs.
Firstly, what sort of 0-60 times have people been getting?
Secondly, any tips on techiques, such as starting revs, gear change points and throttle control.

I would like to get my 0-60 tim down to sub 5.5 secs, so any advice is welcome.

Gary

[shadowninja]

What's your launch like? And tyres? 4 litre engines do have a nice push in the back...

Edited by shadowninja on Sunday 30th March 18:31

[poorpeet]

If you try to match the 0-60 times mentioned you will just bugger the clutch & poss damage the gear box, diff & drive shafts.
The reason you can't match it is probably due to an inbuilt sence of mechanical sympathy & the realisation that you pay the bills.
Road testers & test drivers switch off the first & don't need to worry about the second. IMHO

[spend]

If you ever happen to be somewhere where you can get & keep your tyres nice and hot, the difference in take off will probably amaze you I'm pretty sure even the worst 400 would easily break traction in low gear..

Dave

[MADMAX2]

bring it over to mine i will get sub 5 seconds 0-60!! have to sign a disclaimer form first lol

[v8 racing]

I wouldn't have thought those times to shabby? you would seriously struggle to get below 6 secs to a genuine 60 in a stock 400.

[jsr]

v8 racing said:

I wouldn't have thought those times to shabby? you would seriously struggle to get below 6 secs to a genuine 60 in a stock 400.

Have to disagree.

I have a standard 400 and have recorded a 5.3s on my data logger. This was on a dirty surface and so there was some wheel spin at the start. I can repeatedly achieve 5.5-5.8s if the launch is less than perfect. On a better surface, i reckon i can go a tenth or two faster, but my problem is getting the car off the line. My time to 10 mph is very slow!

Too much wheel spin and the time is ruined, giving over 6 secs. I'm no expert, but find the best way too launch is to use about 2000rpm at most. I honestly believe that on a grippy drag strip with hot tyres, a standard 400 in the hands of an expert driver could achieve a sub 5 second time to 60mph.

Dont forget, there is a roadtest in the Bible which records a time of 4.7 secs for a standard 400,.

[4535jacks]

I have tried starting with low revs (1500-2000) and high revs(4000), with 4000 rpm there is a small amount of wheel spin and with both, I change up at 6000rpm. But both come out at around 6.8 secs. This is using someone with a stopwatch which will have inherent inaccuracies but not as much as +/-1.5 secs!! When is the optimum time to change gear for maximum straight line acceleration?

[tvr5000]

4535jacks said:

I have tried starting with low revs (1500-2000) and high revs(4000), with 4000 rpm there is a small amount of wheel spin and with both, I change up at 6000rpm. But both come out at around 6.8 secs. This is using someone with a stopwatch which will have inherent inaccuracies but not as much as +/-1.5 secs!! When is the optimum time to change gear for maximum straight line acceleration?

Change at around 5k. You have loads of torque so this lets you do what may feel a lethargic 0-60, but you will be suprised. Cant comment on what your time can be but anything over late 5's to 6 and I would pop her into someone that can let you know if it is down to the engine. Theres loads out there in different states and some just need setting up correctly.

If ya still struggle get a 5ltr. Sounds like you're ready for the next step!!

[v8 racing]

jsr said:

v8 racing said:

I wouldn't have thought those times to shabby? you would seriously struggle to get below 6 secs to a genuine 60 in a stock 400.

Have to disagree.

I have a standard 400 and have recorded a 5.3s on my data logger. This was on a dirty surface and so there was some wheel spin at the start. I can repeatedly achieve 5.5-5.8s if the launch is less than perfect. On a better surface, i reckon i can go a tenth or two faster, but my problem is getting the car off the line. My time to 10 mph is very slow!

Too much wheel spin and the time is ruined, giving over 6 secs. I'm no expert, but find the best way too launch is to use about 2000rpm at most. I honestly believe that on a grippy drag strip with hot tyres, a standard 400 in the hands of an expert driver could achieve a sub 5 second time to 60mph.

Dont forget, there is a roadtest in the Bible which records a time of 4.7 secs for a standard 400,.

I hear what you are saying, and just briefly your starting at about 2000 rpm is about spot on! that is around what i use and then just use the throttle in 3 stages to minimise wheelspin, upto know it has worked for me as i have never been beaten of the grid by anyone!!, but seriously dont forget i drive these cars everyday from stock to very modified and if they are saying a stock 400 can do it in 4.7 secs one of my 5.5 litre ones feels like it will do it in 2!!, which is obviosuly rubbish, i also drive a bmw 540 estate for my everday car with a 60 time of 6 secs and that would wipe the floor with a 400, i really dont believe the times of the 4.7, and knowing tvr when they gave a car to do this it more than likely had a 500 engine in it, lets not forget a 400 non hc makes no more than 200 bhp from new!! (real figures)

[4535jacks]

has anyone else clocked sub 6 secs 0 to 60 times in a standard 400?

[v8 racing]

4535jacks said:

has anyone else clocked sub 6 secs 0 to 60 times in a standard 400?

Also another thing to consider which could be being over looked here is the difference between "standard" 400's, some are what i call stock being a rangey engine with a very mild cam, to a hc with big valves i am not going to go down the road of what is this what is that but they do vary a lot!

[im]

Ah



My first ever post...

http://www.pistonheads.co.uk/gassing/topic.asp?h=0...

Has loads of opinion/views etc on just this subject.

I was a TVR virgin back then - salad days...

Bottom line IIRC - If all things are equal you aren't going to make 4.7 or 4.9 without ripping the guts out of it. You might do it once...or twice...but then have your cheque book at the ready.
These cars aren't dragsters they are quick roadsters.

Yeah, you can say rubbish driver/poor car but it was probably an average driver in an average 4L Chimaera.

Edited by im on Sunday 30th March 22:02

[anonymous-user]

v8 racing said:

jsr said:

v8 racing said:

I wouldn't have thought those times to shabby? you would seriously struggle to get below 6 secs to a genuine 60 in a stock 400.

Have to disagree.

I have a standard 400 and have recorded a 5.3s on my data logger. This was on a dirty surface and so there was some wheel spin at the start. I can repeatedly achieve 5.5-5.8s if the launch is less than perfect. On a better surface, i reckon i can go a tenth or two faster, but my problem is getting the car off the line. My time to 10 mph is very slow!

Too much wheel spin and the time is ruined, giving over 6 secs. I'm no expert, but find the best way too launch is to use about 2000rpm at most. I honestly believe that on a grippy drag strip with hot tyres, a standard 400 in the hands of an expert driver could achieve a sub 5 second time to 60mph.

Dont forget, there is a roadtest in the Bible which records a time of 4.7 secs for a standard 400,.

I hear what you are saying, and just briefly your starting at about 2000 rpm is about spot on! that is around what i use and then just use the throttle in 3 stages to minimise wheelspin, upto know it has worked for me as i have never been beaten of the grid by anyone!!, but seriously dont forget i drive these cars everyday from stock to very modified and if they are saying a stock 400 can do it in 4.7 secs one of my 5.5 litre ones feels like it will do it in 2!!, which is obviosuly rubbish, i also drive a bmw 540 estate for my everday car with a 60 time of 6 secs and that would wipe the floor with a 400, i really dont believe the times of the 4.7, and knowing tvr when they gave a car to do this it more than likely had a 500 engine in it, lets not forget a 400 non hc makes no more than 200 bhp from new!! (real figures)

I can't really believe that a 540 will 'wipe the floor' with a decent 400 though....

Edited by BagOfOldRats on Sunday 30th March 21:54

[spend]

Were there 400's with Big Valves? possibly on Wedges, but haven't heard of any in Griff/Chims

Dave

[daz the plumber]

mine is under 5 seconds every time

[daz the plumber]

mine is under 5 seconds every time, ask my girl freind

[spend]

I'm sorry it must be mail for you which I keep deleting, shall I forward it?

[shadowninja]

4535jacks said:

I change up at 6000rpm.

Don't you get engine cut at this rpm?

[im]

4535jacks said:

I change up at 6000rpm.

When do you bounce off your limiter?