What power output should I expect for the 450
Discussion
I've always felt my 450 wasn't as quick as it should be, especially on the track....this was proved last month when I took it to a rolling road. 150bhp....no wonder!! With a bit of tweeking this improved to 200bhp at the end of the day. However, should I expect more & can I get more horses without too much hefty cost?? The car is fairly standard with it's set up - it does have a megasquirt ECU, fast cam, improved cold air ducting plus I had to add 2 extra silencers to comply with noise regulations when I first registered the car over here in Oz (not sure of the impact here!). Cheers
Think TVR quoted 320 bhp for the 450. Probably a bit lower than that- 270-280 ? as tvr were always a bit generous with thier bhp figures. Take in a bit of wear&tear and I would be looking for 250 bhp ish today. The extra silencing might be restricting the exhaust , as said check valve lift. Also a compression test would give an indication to the health of the engine.
The engine that I inherited is a Replacement Rover cross-bolted V8 engine, now 4600cc, utilising a multi-spark ignition system, Edelbrock inlet manifold with a four barrel Edelbrock carburettor. It has a redesigned exhaust system incorporating separate twin outlet pipes requiring small changes to rear bodywork and tuned to make the car quieter.
When the first stage of the rebuild had been completed it was rolling road tested. I recall it developed about 240 bhp at the wheels, which I understand will be approximately 320 bhp at the flywheel. I would like the performance to be a bit quicker in acceleration, but it suites my needs.
When the first stage of the rebuild had been completed it was rolling road tested. I recall it developed about 240 bhp at the wheels, which I understand will be approximately 320 bhp at the flywheel. I would like the performance to be a bit quicker in acceleration, but it suites my needs.
Edited by Henry Harris on Tuesday 12th February 20:52
Russell Mc said:
How old is the cam? Have you checked the lift is what it should be and it's timed up properly?
A good rolling road would of checked the timing and even would of checked the compression in each cylinder if it was down on power..Ideally the timing should be set from the original 8 Degrees BTDC down to 4 Degrees BTDC..Some cars have needed as much as 20..
..But it was realised that the timing marks on the pulley were incorrect when the units came from rover..Cam wear is a major factor in loss of horsepower..Check the compression..Perhaps someone can advise on a healthy reading?....Cheers..Ziga
Edited by mrzigazaga on Monday 11th February 11:04
Henry Harris said:
When the first stage of the rebuild had been completed it was rolling road tested. I recall it developed about 240 bhp at the wheels, which I understand will be approximately 320 bhp at the flywheel. I would like the performance to be a bit quicker in acceleration, but it suites my needs.
Think you been told some porkies there, transmission loss is around 17%, and to loose 120bhp is lot.blaineuk said:
Henry Harris said:
When the first stage of the rebuild had been completed it was rolling road tested. I recall it developed about 240 bhp at the wheels, which I understand will be approximately 320 bhp at the flywheel. I would like the performance to be a bit quicker in acceleration, but it suites my needs.
Think you been told some porkies there, transmission loss is around 17%, and to loose 120bhp is lot.I would think that these are the sort of figures hueb should be getting so there's a few missing ponies in there somewhere fella
Hi Clive,
A previous owner of my 450SE has had a readout from a rolling road giving my car 281bhp in third gear at 5000rpm from the flywheel, or so it says! Apparently it was done at the Big Bad Wedge Fest in 2008 on a trailer so I don't know how accurate a figure it is. I know the official figure is supposed to be 319bhp for the 450 and my car's engine has had a lot done to it so something doesn't add up! All I know is it has enough power for me.
Nick
A previous owner of my 450SE has had a readout from a rolling road giving my car 281bhp in third gear at 5000rpm from the flywheel, or so it says! Apparently it was done at the Big Bad Wedge Fest in 2008 on a trailer so I don't know how accurate a figure it is. I know the official figure is supposed to be 319bhp for the 450 and my car's engine has had a lot done to it so something doesn't add up! All I know is it has enough power for me.
Nick
1BigBadWedger said:
A previous owner of my 450SE has had a readout from a rolling road giving my car 281bhp in third gear at 5000rpm from the flywheel, or so it says! Apparently it was done at the Big Bad Wedge Fest in 2008 on a trailer so I don't know how accurate a figure it is. I know the official figure is supposed to be 319bhp for the 450 and my car's engine has had a lot done to it so something doesn't add up! All I know is it has enough power for me.
It adds up fine. The 450 power graph is a bit odd and has a dip in it about two thirds the way up; the power is made very high. 281 at 5000 rpm sounds on track for a 300bhp+ max reading, even given the variables of r/r.Rockettvr said:
That's still 25% though. I would suggest that if he's got 240 bhp at the wheels then he should have more like 280-290 at the flywheel if your figure of 17% transmission loss is accurate. Think his rolling road guy has overstated the flywheel figure a bit.
Your maths is correct but 17% is high.Dyno figs are all subjective especially mobile roller units as has been covered at great length on the various forums. I use a FIA accredited hub dyno not far from me and have used them for the last couple of years. Their system at least calculates whats at the fly and more importantly what gets to the hubs which really is the important number. The other thing I like is they then have my historic runs on their database for comparison / consistency. To be honest I really only do it to make sure the engine is healthy!
Chris
Chris
gsx600 said:
TA14 said:
Remember that Henry and gsx have the later engine which was/is about 15% down on power.
Don't think mine was much later than a later 450, not cross bolted or anything , circa 1992 if I remember correctly.hueb said:
Thanks all for the input. For information, in 2009 the car had a new 'short' engine with Piper Camshaft kit. I'll start by making sure the timing / compression was done during the rolling road test (it wasn't a mobile rolling road) in my quest for those missing horses!! Cheers Clive
I see. In that case expect nearer 240 to 250 bhp.
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