Cost effective way of getting 300-350hp
Discussion
I'll try and start off by explaining the background to this request ;
I've had my 4.0HC for a while now and I absolutely love it. The noise it makes, the way it looks, the colour, the smell, everything.
However, I'm starting to feel its somewhat underpowered for the drama and the noise it makes. I've had it tested and it makes about 215bhp, but I'm seriously thinking it needs more, a lot more
This was rather abruptly hammered home to me when a BMW 535d smoked me on a dual carriageway slip road a couple of weeks ago and also I've realised how much faster cerbera's are too
Realistically, I'd love to hang onto my Chim, but I honestly think that if it's going to be everything I crave, it's going to need at least 300-350hp which is a massive step up from where it is now.
I did originally look at chopping it in for a 4.5 Cerb, and I've still got that niggle there, but a) I love open top motoring, and b) I'm planning on trading in the family company car and getting an B7 RS4 avant, so that'll cover the times in need a blast car with more than 1 passenger (ie, when there's no bbsitters available)
The question I have though, which I'm hoping the collective knowledge of PH can help answer is ;
What's the best and most cost effective way of getting 300+ bhp from my 50k miles 95 sepr engined 4.0Hc ? Is it going to be sourcing a 2nd hand 5.0 engine and mildly tuning it, or would the supercharger or turbo charger route be a better solution
I understand I'll need to look at the suspension too as I'm pretty sure my current std set up would struggle with more power, but does anyone have a rough idea of how much im going to need to spend to get this power....without telling the mrs
And is this massive leap in power likely to reaffirm my position as one of the fastest, most fun cars on the normal road ?
Any help or advice would be greatly appreciated
Thanks
Graeme
Swindon
I've had my 4.0HC for a while now and I absolutely love it. The noise it makes, the way it looks, the colour, the smell, everything.
However, I'm starting to feel its somewhat underpowered for the drama and the noise it makes. I've had it tested and it makes about 215bhp, but I'm seriously thinking it needs more, a lot more
This was rather abruptly hammered home to me when a BMW 535d smoked me on a dual carriageway slip road a couple of weeks ago and also I've realised how much faster cerbera's are too
Realistically, I'd love to hang onto my Chim, but I honestly think that if it's going to be everything I crave, it's going to need at least 300-350hp which is a massive step up from where it is now.
I did originally look at chopping it in for a 4.5 Cerb, and I've still got that niggle there, but a) I love open top motoring, and b) I'm planning on trading in the family company car and getting an B7 RS4 avant, so that'll cover the times in need a blast car with more than 1 passenger (ie, when there's no bbsitters available)
The question I have though, which I'm hoping the collective knowledge of PH can help answer is ;
What's the best and most cost effective way of getting 300+ bhp from my 50k miles 95 sepr engined 4.0Hc ? Is it going to be sourcing a 2nd hand 5.0 engine and mildly tuning it, or would the supercharger or turbo charger route be a better solution
I understand I'll need to look at the suspension too as I'm pretty sure my current std set up would struggle with more power, but does anyone have a rough idea of how much im going to need to spend to get this power....without telling the mrs
And is this massive leap in power likely to reaffirm my position as one of the fastest, most fun cars on the normal road ?
Any help or advice would be greatly appreciated
Thanks
Graeme
Swindon
You wont get smoked by any oil burner then 
as well as anyone could...First, let's do some sums:
BMW 535d: 308 bhp, 1725 kg = 180 bhp/tonne
Your Chimaera: 215 bhp, 1060 kg = 203 bhp/tonne
So, your Chimaera should have had the advantage in acceleration at moderate speeds. The BMW's overall power advantage would only have kicked in at higher speeds where power-to-weight becomes less important than power-to-drag. Even if the BMW were remapped, your Chimaera should have held its own.
Are you sure you weren't just caught in the wrong gear? The TVR's engine doesn't really wake up until at least 3,500 rpm, so if you just floored it at lower rpm and relied on the torque then you were bound to lose out - especially if the BMW was an auto which would have chosen the optimum gear.
Also, I agree that 215 bhp doesn't sound like much for a 4.0 HC, unless as suggested it's a wheel figure. Perhaps your money should be spent diagnosing how your current engine could be brought back to the sort of power it should have?
BMW 535d: 308 bhp, 1725 kg = 180 bhp/tonne
Your Chimaera: 215 bhp, 1060 kg = 203 bhp/tonne
So, your Chimaera should have had the advantage in acceleration at moderate speeds. The BMW's overall power advantage would only have kicked in at higher speeds where power-to-weight becomes less important than power-to-drag. Even if the BMW were remapped, your Chimaera should have held its own.
Are you sure you weren't just caught in the wrong gear? The TVR's engine doesn't really wake up until at least 3,500 rpm, so if you just floored it at lower rpm and relied on the torque then you were bound to lose out - especially if the BMW was an auto which would have chosen the optimum gear.
Also, I agree that 215 bhp doesn't sound like much for a 4.0 HC, unless as suggested it's a wheel figure. Perhaps your money should be spent diagnosing how your current engine could be brought back to the sort of power it should have?
The OP is asking for the most cost effective way to get into the higher bhp regions for a Chimaera.
The most cost effective and simplest route would be a 75 shot of nitrous.
A decent kit could be bought brand new for about £600 and would instantly be quicker than most 500's.
Obvious downsides.... An 11lb bottle will cost approx £55 to fill and on a 75 shot would give you about 3 minutes of 100% use.
This 'could' last weeks in real terms on the road. Or 15+ runs on a drag strip.
The most cost effective and simplest route would be a 75 shot of nitrous.
A decent kit could be bought brand new for about £600 and would instantly be quicker than most 500's.
Obvious downsides.... An 11lb bottle will cost approx £55 to fill and on a 75 shot would give you about 3 minutes of 100% use.
This 'could' last weeks in real terms on the road. Or 15+ runs on a drag strip.
dbv8 said:
The OP is asking for the most cost effective way to get into the higher bhp regions for a Chimaera.
The most cost effective and simplest route would be a 75 shot of nitrous.
A decent kit could be bought brand new for about £600 and would instantly be quicker than most 500's.
Obvious downsides.... An 11lb bottle will cost approx £55 to fill and on a 75 shot would give you about 3 minutes of 100% use.
This 'could' last weeks in real terms on the road. Or 15+ runs on a drag strip.
But can you find a insurer that will cover it for use on the road? I could not when i had my kit and that's why i sold up in the end. I did not personally want to run the risk but up to the user at the end of the day i guess. I only paid £300 for my WON kit with lots of trick bits and it could do up to 150bhp shot off e-bay The most cost effective and simplest route would be a 75 shot of nitrous.
A decent kit could be bought brand new for about £600 and would instantly be quicker than most 500's.
Obvious downsides.... An 11lb bottle will cost approx £55 to fill and on a 75 shot would give you about 3 minutes of 100% use.
This 'could' last weeks in real terms on the road. Or 15+ runs on a drag strip.
dbv8 said:
The OP is asking for the most cost effective way to get into the higher bhp regions for a Chimaera.
The most cost effective and simplest route would be a 75 shot of nitrous.
A decent kit could be bought brand new for about £600 and would instantly be quicker than most 500's.
Obvious downsides.... An 11lb bottle will cost approx £55 to fill and on a 75 shot would give you about 3 minutes of 100% use.
This 'could' last weeks in real terms on the road. Or 15+ runs on a drag strip.
15 runs x 11.5 sec/run = 172.5 seconds = ...The most cost effective and simplest route would be a 75 shot of nitrous.
A decent kit could be bought brand new for about £600 and would instantly be quicker than most 500's.
Obvious downsides.... An 11lb bottle will cost approx £55 to fill and on a 75 shot would give you about 3 minutes of 100% use.
This 'could' last weeks in real terms on the road. Or 15+ runs on a drag strip.
Honestly, I don't think even the Chinm's boot would be big enough for all the bottles I would need
However, for occasionally tearing off a strip of Euro-box ass... point taken (more or less).
scotty_d said:
But can you find a insurer that will cover it for use on the road? I could not when i had my kit and that's why i sold up in the end. I did not personally want to run the risk but up to the user at the end of the day i guess. I only paid £300 for my WON kit with lots of trick bits and it could do up to 150bhp shot off e-bay
There are more and more insurers getting involved now. I am with Adrian Flux who undercut Haggertys. I believe Swintons and others have started quoting also.Hi all
The 215 was at the wheels, so I'd assume around 240ish at the fly.
I understand the bhp/tonne calculation for the 535d BMW, but it's the monstrous amount of torque available in those things about about 60 that really left me making lots of noise in third, but not catching him up.
I've never dragged or properly tested my cars acceleration figures, but for what it's worth my iPhone dynolicious app (which is I expect is undoubtably of dubious accuracy) has recorded 5.2seconds 0-60 with a launch with some mechanical sympathy from myself with the clutch
To be honest, I'm not over keen on the nitrous route as, as mentioned, it takes up most of the boot and is likely to run out just at the point I really need it.
The 215 was at the wheels, so I'd assume around 240ish at the fly.
I understand the bhp/tonne calculation for the 535d BMW, but it's the monstrous amount of torque available in those things about about 60 that really left me making lots of noise in third, but not catching him up.
I've never dragged or properly tested my cars acceleration figures, but for what it's worth my iPhone dynolicious app (which is I expect is undoubtably of dubious accuracy) has recorded 5.2seconds 0-60 with a launch with some mechanical sympathy from myself with the clutch
To be honest, I'm not over keen on the nitrous route as, as mentioned, it takes up most of the boot and is likely to run out just at the point I really need it.
graeme4130 said:
Hi all
The 215 was at the wheels, so I'd assume around 240ish at the fly.
I understand the bhp/tonne calculation for the 535d BMW, but it's the monstrous amount of torque available in those things about about 60 that really left me making lots of noise in third, but not catching him up.
I've never dragged or properly tested my cars acceleration figures, but for what it's worth my iPhone dynolicious app (which is I expect is undoubtably of dubious accuracy) has recorded 5.2seconds 0-60 with a launch with some mechanical sympathy from myself with the clutch
To be honest, I'm not over keen on the nitrous route as, as mentioned, it takes up most of the boot and is likely to run out just at the point I really need it.
Fair enough. Gas is only for the more insane of us who just want to go as quickly as possible on a budget.The 215 was at the wheels, so I'd assume around 240ish at the fly.
I understand the bhp/tonne calculation for the 535d BMW, but it's the monstrous amount of torque available in those things about about 60 that really left me making lots of noise in third, but not catching him up.
I've never dragged or properly tested my cars acceleration figures, but for what it's worth my iPhone dynolicious app (which is I expect is undoubtably of dubious accuracy) has recorded 5.2seconds 0-60 with a launch with some mechanical sympathy from myself with the clutch
To be honest, I'm not over keen on the nitrous route as, as mentioned, it takes up most of the boot and is likely to run out just at the point I really need it.
The dynoliscious app is very good. If you have the settings right and the gadget mounted firmly and flat in the car it can be very accurate.
I ran mine at York a couple of years ago and ran a 12.1. The app showed 12.3 and was also within 2 mph.
Dr Mike Oxgreen said:
First, let's do some sums:
BMW 535d: 308 bhp, 1725 kg = 180 bhp/tonne
Your Chimaera: 215 bhp, 1060 kg = 203 bhp/tonne
So, your Chimaera should have had the advantage in acceleration at moderate speeds. The BMW's overall power advantage would only have kicked in at higher speeds where power-to-weight becomes less important than power-to-drag. Even if the BMW were remapped, your Chimaera should have held its own.
Are you sure you weren't just caught in the wrong gear? The TVR's engine doesn't really wake up until at least 3,500 rpm, so if you just floored it at lower rpm and relied on the torque then you were bound to lose out - especially if the BMW was an auto which would have chosen the optimum gear.
Also, I agree that 215 bhp doesn't sound like much for a 4.0 HC, unless as suggested it's a wheel figure. Perhaps your money should be spent diagnosing how your current engine could be brought back to the sort of power it should have?
I think we would need to look at the relative torque curves as the BMW will probably develop its max bhp at a lower and often more accessible rev range than a petrol engine. The RV8 does benefit from having a flat torque curve. Having driven a 535d extensively I would suggest that its mid range acceleration is better than a 4.0 RV8 and possibly better than the bigger versions too. 50-70 time in gear will give an idea.BMW 535d: 308 bhp, 1725 kg = 180 bhp/tonne
Your Chimaera: 215 bhp, 1060 kg = 203 bhp/tonne
So, your Chimaera should have had the advantage in acceleration at moderate speeds. The BMW's overall power advantage would only have kicked in at higher speeds where power-to-weight becomes less important than power-to-drag. Even if the BMW were remapped, your Chimaera should have held its own.
Are you sure you weren't just caught in the wrong gear? The TVR's engine doesn't really wake up until at least 3,500 rpm, so if you just floored it at lower rpm and relied on the torque then you were bound to lose out - especially if the BMW was an auto which would have chosen the optimum gear.
Also, I agree that 215 bhp doesn't sound like much for a 4.0 HC, unless as suggested it's a wheel figure. Perhaps your money should be spent diagnosing how your current engine could be brought back to the sort of power it should have?
Mods to a 400 will cost lots and lots of money to get any decent power gains as the intake side is very restricted.
You will immediately be wanting to take the inlet side out to 45mm which will mean new heads as the 400 heads have not got very large valves in them. That coupled to a new cam, new plenum trumpets, inlet manifold etc will be over a grand just in bits straight away(with 2nd hand heads). Oh and add a new ECU and mapping on top so thats another £one.
Then to get decent "bang for buck" you will probably be looking at an SC kit so add another 4-5k on the top.
Sadly the best option is to sell your car and add £5k on the top to buy a 500 or a tuscan / tamora - there is a low mileage Tuscan on Fleabay at the moment for £11.5k! If you buy a 500 engine and put it in your 400 you will have all the hassles of the swap, followed by questions at selling time about why the wrong engine is in the car; that and the cost of the inevetable strip down, inspect and rebuild unless you are going to fit the engine and simply hope it runs well.
The sale/swap way gets you an instant hit too, rather than months without your car and then endless worrying and fiddling.
You will immediately be wanting to take the inlet side out to 45mm which will mean new heads as the 400 heads have not got very large valves in them. That coupled to a new cam, new plenum trumpets, inlet manifold etc will be over a grand just in bits straight away(with 2nd hand heads). Oh and add a new ECU and mapping on top so thats another £one.
Then to get decent "bang for buck" you will probably be looking at an SC kit so add another 4-5k on the top.
Sadly the best option is to sell your car and add £5k on the top to buy a 500 or a tuscan / tamora - there is a low mileage Tuscan on Fleabay at the moment for £11.5k! If you buy a 500 engine and put it in your 400 you will have all the hassles of the swap, followed by questions at selling time about why the wrong engine is in the car; that and the cost of the inevetable strip down, inspect and rebuild unless you are going to fit the engine and simply hope it runs well.
The sale/swap way gets you an instant hit too, rather than months without your car and then endless worrying and fiddling.
Edited by M@H on Monday 12th December 12:35
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