Engine upgrade

[Boner]

i have a standard 4.0 chimaera and thinking about an engine mod to increase power. What is the best option and the costs? Graham

[.mark]

I would have thought the best option would be to buy a 4.5 or 5 litre. Mods are OK but then the car isn't standard so insurance would go up. If you were trying to sell it potential buyers may be put off by a modded engine. Plus any repairs would probably be dearer too. Have a look on the TVR Car Club mail list there was recently a lot flying around about modding engines and some really top tips from resident 'tuners' Peter Humphries and Steve Heath. Who know a hell of a lot more than my ramblings!! All IMHO of course.

[johnwilk]

Buy a 5 Litre. You will be astounded by the difference in performance. I switched from a 4.0 to my present Chimaera 500. You simply cannot believe the difference. PS My car is still for sale as I have a new Tuscan coming in September (see Starmist green T Reg 500 in the for sale section)

[trefor]

Agreed, get a 5.0 litre - you'll end up spending a lot on tuning and still have less power than a std 5.0 litre if you're not careful.

[manek]

Agree entirely. I've investigated the costs of upgrading and it's high: a new, bigger engine is cheaper. The other option is to swap the whole car. Get it right and the cost could be negligible. Hoever, taking this route you swap a set of known issues for a set of unknown ones. Whether you want to make that leap is a question only you can answer...

[graham]

It also depends if you've done anything else to the car, mines got bigger brakes and uprated suspension, so id need to do that again if i swap the car for a 5ltr, so looks like my only option is a new engine for mine.. about 7k for an absolute nutter jobby with more power than a 5ltr tvr lump hee hee... a mate just had the same problem though swapped his 97 4ltr for a 99 5ltr cost him 9k to change but he gets a newer car as well ( but he doesnt have my brakes suspension or flames ) Edited by graham on Tuesday 24th July 17:29

[Boner]

Cheers guys, Best start saving for the 5ltr then! Graham

[cockers]

Don't want to be controversial here, but apart from instant grunt (even at tickover), I didn't feel that the 500 was that much different to the 400 when the revs get up a bit. I've driven two Griff 500s and a Chimaera 500 now, so I've banished any thoughts I had that I may have just driven a wrong 'un. Anyway, the upshot is that I saved myself a few grand and went 4ltr. Still, that's just my opinion...

[trefor]

One thing - I think insurance for a std 4.0L and a std 5.0L is about the same, but if you have a modified 4.0L then won't the insurance put the premium up by say 10% per 'mod' (quoting % from past experience on a Nissan 200). Sounds daft I know, but I suspect it is the case.

[GreenV8S]

quote:Don't want to be controversial here, but apart from instant grunt (even at tickover), I didn't feel that the 500 was that much different to the 400 when the revs get up a bit.

Quite surprised to read that comment because the 500 should be more powerful across the board, and put out dramatically more torque at low/mid revs. Granted the 500 runs into breathing limitations sooner and the top end drops off quicker than the 400, but you wouldn't normally run that high revs? Compare the two cars back to back (or side by side, on a track) and the difference is clear, the 500 is significantly faster. Cheers, Peter Humphries (and a green V8S)

[cockers]

As I recall, there's about a second in it to 60 and three seconds to 100 (not that 0-whatever measures are particularly useful), which may be noticeable, but is in a similar league. Agree about the torque though. In gear times are doubtless quicker in a 500. Maybe I just drove the 500s differently, because of the massive torque at the bottom end, whereas I use the gearbox more in my 400.

[Trefor]

I had a Griff 500 loaner one day while my 4.0L Chimaera was being serviced. The Griff was a lot quicker low down the rev range due to gollops more torque. I guess once you get moving and further up the rev range the difference is less noticable. I do know a Griff 500 is distinctly faster than my Chimaera (which is nice 'n heathly BTW). Of course on the public road it doesn't make that much difference as you'll still pass those slow cars/burn Mr Mondeo off at the lights with either engine. T/.

[yum]

This website really lives up to its name... we are talking a difference of 0.5 of a second to 60! My suggestion would be to learn how to drive the 4L faster first. Mine's a 4L, and in the hands of an instructor at Mallory (me holding on for dear life in the passenger seat) we were overtaking griff 500s and cerberas. R

[shak]

I went through this state of mind (I MUST have more POWER!)shortly after getting my Chimaera 4 litre partly because it was a bit flat in the 1500-2700ish rev range.Had it rechipped and mapped by Mark Adams and it did make a huge difference to the torque and smoothness in the low-midrange.Costs about £500-ish with rolling road etc. Definitely recommended if you don't want to fork out thousands on upgrades to the engine proper or a 5 litre.Oh yes,Magnecor r-100 ignition leads also eliminated some of those flat spots and they look excellent. Insurance-5% premium Pete Humphries gave me lots of advice at the time on the site.Thanks Pete for saving my bank balance!

[apache]

how much and where for the magnacores

[shak]

Demon Tweeks-motorsport catalogue.Aboot £150(INC vat) if I remember . Mark Adams also sells them I think and ACT products who you can get through the links page or through Sprint. Incidentally it also reduced noise interference on the cd/radio.(yup-I'm a sad hi-fi buff as well!) Happy hunting.

[apache]

ta

[jamieheasman]

5.0litre cars are in a different league to the 4.0litre cars. I've driven plenty and owned a few and there's a world of difference. Driver training will allow you to go faster in the car. Bigger brakes and suspension (which you already have) is more significant around a circuit than another 80bhp or so. Without going mad, you could go for an enlarged plenum, flowed and ported inlet manifold and shorter, wider trumpets*, followed by a Mark Adams remap. The trumpets in the 4.0litre almost touch the plenum roof and are totally unsuitable for a sportscar but fine on a Range Rover. If your car is old enough or you just don't care (or know a friendly MOT centre) I'd recommend getting the car decatted at the same time. I got a straight 15bhp increase without any other mods and the throttle response is much better. *RPI and most other specialists offer a package of upgrades for this for less than a grand, should give you another 20bhp at least and improve breathing greatly further up the rev-range.

[RobM]

I upgraded from 4 to 5 ltr. The difference is very very noticeable, especial in 3rd, midrange 50-70. btw,although its only .5 second to 60, thats nearly 15% more G. and if G==FUN, who needs brakes suspension or flames? Also, Here's some results from a 50-70 fun session with Grahams G meter. No driver skill involved, just floor it in 3rd and hold on Start Speed 50.0mph mph s g ft hp 60.0 1.32 0.36 106 212 70.0 2.64 0.33 232 237 Pk Power: 69.4mph 2.55s 223ft 241hp Peak G: 61.8mph 1.54s 126ft 0.36g i remember easing off at 70, so i did a 2nd run 50-80... Start Speed 50.0mph mph s g ft hp 60.0 1.26 0.35 101 208 70.0 2.53 0.34 223 241 80.0 3.88 0.31 372 264 Pk Power: 77.9mph 3.57s 336ft 272hp Peak G: 69.5mph 2.45s 214ft 0.37g G meter was setup for weight of 4.0 ( graham did it on a weigh bridge !! ) 5.0 chim is about 100 kilo's more i think, so the Hp at wheels may be a bit optimistic Edited by RobM on Thursday 9th August 23:00