Differences between 400 and 400HC
Discussion
http://ourworld.compuserve.com/homepages/Peter_Beech/TVR/engspec.htm
I was looking at the specs on the 400 and 400HC engines and thinking that the HC has a lot of extra power. What are the mechanical differences between the engines (other than the compression ratio
)
I am guessing different ignition map, but what about the internals. I can see the cam and chain drive are different, but there must be others.
In other words, can I skim a load of the head and remap the ignition for an extra 35 hp.
Z
I was looking at the specs on the 400 and 400HC engines and thinking that the HC has a lot of extra power. What are the mechanical differences between the engines (other than the compression ratio
) I am guessing different ignition map, but what about the internals. I can see the cam and chain drive are different, but there must be others.
In other words, can I skim a load of the head and remap the ignition for an extra 35 hp.
Z
Got a HC and drove a couple of non-HC's before I bought it. Also had a drag race on the Duxford airfield a year or so ago. The HC is SLIGHTLY faster... maybe a little smoother running, but that is probably my engine rather than by design.... On the runway at Duxford I was catching and gaining on the 4.0 cars infront. Eventually I would have passed (remember we are talking about 130MPH so the diferential in speed needs to be a lot to pass in a short period of time)....
Yes they are faster, but not by much. Try a 5.0 and compare the difference - its dramatic. But if there is a 4.0 and its in better nick than a HC then get that one, but if you can and its a cracker get the HC.... your choice, but in reality not a huge amount of difference....
Yes they are faster, but not by much. Try a 5.0 and compare the difference - its dramatic. But if there is a 4.0 and its in better nick than a HC then get that one, but if you can and its a cracker get the HC.... your choice, but in reality not a huge amount of difference....
pbrettle said:
Got a HC and drove a couple of non-HC's before I bought it.
When we were shopping, we didn't care if it was a HC or not. Having picked it up last weekend, it was sold as a "normal" 400, however, on getting it home and starting to explore, the handbook and plenum badge state its a HC. I've spoken to the factory, and they were very helpful (thanks Liz), and for a few quid will send me a full report with the original spec etc, etc.....
Finally, to my question
- if it *is* a HC, do I need to tell my insurance company that it's not a 400, but a 400HC? Will they know the difference? Will they care? Thanks in advance, and sorry for the slight hijack!
I was not really thinking about buying a different car. I think that my V8S only came in 400 spec anyway, with the exception of the V8Sc (different cam and cat).
It was just that an extra 35 hp and more torque seemed a good increase for a cam change and a different fuel map.
If I understand everyone correctly then a different cam and a remap would give HC performance from a stock 400 unit. It would also do this with out making the engine over cammy and trashing the idle.
On paper the differences seem worth the effort, has anyone done this before.
Z
It was just that an extra 35 hp and more torque seemed a good increase for a cam change and a different fuel map.
If I understand everyone correctly then a different cam and a remap would give HC performance from a stock 400 unit. It would also do this with out making the engine over cammy and trashing the idle.
On paper the differences seem worth the effort, has anyone done this before.
Z
In real terms it was no where near the 35 bhp etc that was claimed. To be honest. If you want more horses, enlarge the plenum, get a Jag air flow meter and Mark Adams to chip it. Probbaly cost less and give just as much extra welly.
Steve
www.tvrbooks.co.uk
Steve
www.tvrbooks.co.uk
ByronTVR said:
I think that the HC has bigger valves also... not sure tho 
I might confused it with the 4.3 "Big Valve" Griff.
ByronTVR
The HC has same valve size as standard 4.0L but has polished heads, 4.0L heads are normally untouched, cam is different, total package probably gives an extra 10-15 bhp
Tim
kdd said:
Got a HC and drove a couple of non-HC's before I bought it.
When we were shopping, we didn't care if it was a HC or not. Having picked it up last weekend, it was sold as a "normal" 400, however, on getting it home and starting to explore, the handbook and plenum badge state its a HC. I've spoken to the factory, and they were very helpful (thanks Liz), and for a few quid will send me a full report with the original spec etc, etc.....
Finally, to my question
Thanks in advance, and sorry for the slight hijack!
To be honest, I found the car and it was advertised as a 400 and it turned out to be a HC. No mis-interpretation from the dealer, just something that they didnt consider to be much of a difference. To be it was a bonus rather than a selling point.
As for telling the insurance company - YES you must. The 400HC was a different model and in the current climate with insurance companies, you must get every detail correct - and that means saying that it is a 400HC. This should not make any difference to the premiums, but should you stack it there is one less loop hole for them to get out paying you for.
Yes, they will know the difference - it should say on the V5 as it is a bone fide model. Check the V5 and the owners manual for the correct info.
pbrettle said:
To be honest, I found the car and it was advertised as a 400 and it turned out to be a HC. No mis-interpretation from the dealer, just something that they didnt consider to be much of a difference. To be it was a bonus rather than a selling point.
Exactly. I hope I didn't imply the dealer deceived us in any way, that wouldn't be true at all!
pbrettle said:
As for telling the insurance company - YES you must. The 400HC was a different model and in the current climate with insurance companies, you must get every detail correct - and that means saying that it is a 400HC. This should not make any difference to the premiums, but should you stack it there is one less loop hole for them to get out paying you for.
Yes, they will know the difference - it should say on the V5 as it is a bone fide model. Check the V5 and the owners manual for the correct info.
OK. Will give them a call and tell them once it's confirmed one way or the other.
I know what you mean about insurance companies using any possible loophole! Not having had one before, I didn't know if the HC was a distinct model, or just an optional bonus....
The nice helpful lady at the factory is sending me a full report on the car, so not only will it confirm that, it'll tell me all sorts of other stuff I'm interested to know. I don't suspect anything sinister, its just that I've wanted a TVR since I was a kid, and now I've got one I want to know everything about them, and this one in particular
Thanks for your reply,
Karl
Karl - magic to hear you have realised a Dream! Good on you.
For what it's worth, my advice with regard to Insurance companies is to bury them with detail. They can't say they don't understand it, can they?
In general this works well, so the original spec from TVR, any power graphs, any non-standard parts - write down the lot!
Every nut and bolt on both my modifieds is declared, and the Insurance company are very happy about it.
Have fun!
For what it's worth, my advice with regard to Insurance companies is to bury them with detail. They can't say they don't understand it, can they?
In general this works well, so the original spec from TVR, any power graphs, any non-standard parts - write down the lot!
Every nut and bolt on both my modifieds is declared, and the Insurance company are very happy about it.
Have fun!
Mark Adams said:
Karl - magic to hear you have realised a Dream! Good on you.
For what it's worth, my advice with regard to Insurance companies is to bury them with detail. They can't say they don't understand it, can they?
In general this works well, so the original spec from TVR, any power graphs, any non-standard parts - write down the lot!
Every nut and bolt on both my modifieds is declared, and the Insurance company are very happy about it.
Have fun!
Thanks Mark. As far as I can tell it's original, so just waiting for the call from blackpool......
edited to add: blackpool just called to confirm it was a HC when it left them in '96..... next call: insurance company.....
>> Edited by kdd on Thursday 18th December 11:10
To follow on from Marks comments - mines been modified with uprated suspension and brakes. It doesnt cost me a bean more on the insurance as they, in the eyes of the insurance company, "dont improve the performance". In fact they are probably safety modifications anyway - I can stop better (without locking up) and have better handling....
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