Supercharging and Engine Braking

[geordiepingu]

Seeing lots of great results off the SC series kits is making me wonder, is there a noticeable effect on engine braking with a forced induction setup on these cars? The 'cheap power' looks attractive but wondering if it comes at a cost of the characteristics of NA cornering a big brake Chim.

[hoofa]

No difference just feels like a larger capacity engine, however you do need better brakes as you arrive at a corner quicker

[geordiepingu]

That is the dangerous reply of encouragement I was looking for thanks! This sounds like the start of me planning my standalone ECU conversion and then the subsequent Rotrex kit. Keen to see if any PHers at the local TVR CC have one to hoon me about in to be certain

[QBee]

The massive power you can get out of these supercharged or turbocharged set ups is seductive.

So you will do the conversion for one of two reasons:

1. To brag about your car's 598 bhp and 645 ft lbs of torque down the pub and at car meets, but not actually drive it more than 50 miles a year at more than 50 mph (a bit like a guy I know with an Audi RS6 - his granny drives faster, and she's been dead 20 years, but he loves the bragging rights of the 503 bhp 4 litre twin turbo with all the electronic drivers aids) or

2. To actually drive the car to its potential, which means being (even more of) a lunatic on the public roads, or doing track days and other similar events.

If it's 1. as you were, no need to read the rest of this post.

If it's 2. then to produce much over 400 bhp reliably, you will need to rebuild the engine with stronger internals and will definitely need the ECU changed for a more mappable one, as you mention. So that's £6,000, on top of the price of the SC kit, straight off. Plus bigger injectors, fuel pump etc etc.
Much over 500 bhp and you need to be reviewing your clutch, drive train and diff.
Drag racing starts, and you are into a whole new world of wallet pain.
Hoofa (above) has built himself a brilliantly engineered car, and can give better guidance than me on what is needed and the costs because he has done anything you can think of and a few mods beside

Just saying, not to put you off, but to make you aware of what you are getting in to. It's too tempting to go for max power when at the mappers.

Edited by QBee on Monday 31st May 08:33

[QBee]

PS the cheapest way of getting a supercharged car is to buy one already done, with my list of required changes in your hand as you review the car.

[geordiepingu]

Appreciate the detailed response QBee as always. I would hope that my topic title would imply which answer to your question

I'm intending to break the 300rwhp mark. Reasonable figures before we start talking about 400BHP - I have no real goals to go there at the moment. It is a tremendous handler but really does lack pace on the straights - moreso at the minute now that my vacuum advance is broken. Right now I'm in the middle of ditching it to go for a standalone megasquirt setup. Quite the opposite of both points I think. I'm aware that there's always the eventual desire for more power, but I'm sure the annual toy budget will cope with that. I think before I go over 400BHP I'd want to make sure I outgrow a lower power level first and ensure my capability of keeping all 4 tyres on the asphalt at the ring!

[QBee]

If you find yourself further down the A1, come and drive mine.
It’s a turbo, not SC, but has either 325 or 395 bhp at the turn of a knob. And more torque than a 500.
I am one mile off the A1 at Newark.

[geordiepingu]

Appreciate it! I'll give you a shout and perhaps try and catch you for a run out the next time I manage to bring my Chim down. Would've been this June if I was doing the London to Brighton run with my Dad

[450Nick]

QBee said:

The massive power you can get out of these supercharged or turbocharged set ups is seductive.

So you will do the conversion for one of two reasons:

1. To brag about your car's 598 bhp and 645 ft lbs of torque down the pub and at car meets, but not actually drive it more than 50 miles a year at more than 50 mph (a bit like a guy I know with an Audi RS6 - his granny drives faster, and she's been dead 20 years, but he loves the bragging rights of the 503 bhp 4 litre twin turbo with all the electronic drivers aids) or

2. To actually drive the car to its potential, which means being (even more of) a lunatic on the public roads, or doing track days and other similar events.

If it's 1. as you were, no need to read the rest of this post.

If it's 2. then to produce much over 400 bhp reliably, you will need to rebuild the engine with stronger internals and will definitely need the ECU changed for a more mappable one, as you mention. So that's £6,000, on top of the price of the SC kit, straight off. Plus bigger injectors, fuel pump etc etc.
Much over 500 bhp and you need to be reviewing your clutch, drive train and diff.
Drag racing starts, and you are into a whole new world of wallet pain.
Hoofa (above) has built himself a brilliantly engineered car, and can give better guidance than me on what is needed and the costs because he has done anything you can think of and a few mods beside

Just saying, not to put you off, but to make you aware of what you are getting in to. It's too tempting to go for max power when at the mappers.

Edited by QBee on Monday 31st May 08:33

It's not always about power. I was always more interested in torque. BHP is fun on a track, but for real world fun on the road, it's really about the hand of god pushing you into the seat when you press the loud pedal regardless of speed.

[spitfire4v8]

No reason why a supercharger should affect engine braking .. in reality the extra drag of the sc (even off-load recirculating systems have extra drag) will improve it (all other things being equal).

between sc or turbo I'm firmly in the turbo camp because of its easy adjustability for boost, but there are some lovely sc installs out there and they do drive very well .. as hoofa says just like a larger capacity version of what you already have

[macdeb]

Mine was turbo and 573hp/610lb. As someone said earlier it's about torque when you want it pressing the loud pedal now and then. Crikey big oil burners can now shame many TVR's. I did it because I could and not to fall in any camps, I did it to prove it could be done by men in sheds so there are many reasons why someone would want to do it and not just the two previously mentioned and I find that reasoning both tiresome and demeaning tbh. The drivetrain was extensively upgraded. Yes, I went to many shows in it (NEC etc) and was proud to do so, so no shame there. I did not intend to do track days as I did all that many times on many tracks over many years on two wheels being more competent in that mode, besides why risk all my hard work by some nutter in a Clio wiping me out? But I did tour extensively in it; West coast France, South of France, around Italy, Switzerland etc as going around in circles in a car does nothing for me but I wouldn't knock anyone who thinks otherwise The guy who has it now has been to Portugal in it too. Take no notice of self proclaimed driving Gods as it's your car and use it for what you want. 'If' I may offer any advice it would be think about it; Build it right, build it once.

[Engineer1949]

i quite agree with the above as you may or may not know i built my son a 4.0ltr blown chim from a wreck it is on here somewhere the entire build but my point is to start with we used original clutch allbeit new gearbox drive shafts brakes all have since been massivley upgraded bearing in mind the bhp is around 350 so not horrendous brakes are large hispec units 6 pot on the front 4 on the rear shocks all round mcloud clutch after tryinf several others it now has a tko gearbox larger diff hollow hugely expensive drive shafts so on and soforth so as above do it once do it right saves a lot in the long run

john

[rockits]

QBee said:

PS the cheapest way of getting a supercharged car is to buy one already done, with my list of required changes in your hand as you review the car.

I can concur and agree as that is exactly what I did

My Chimaera has had a heck of a lot spent by the previous owner. Circa £40k over his 8 year ownership.

Edited by rockits on Thursday 24th June 19:22

Edited by rockits on Thursday 24th June 19:22

[Classic Chim]

rockits said:

I can concur and agree as that is exactly what I did

My Chimaera has had a heck of a lot spent by the previous owner. Circa £40k over his 8 year ownership.

Edited by rockits on Thursday 24th June 19:22

Edited by rockits on Thursday 24th June 19:22

The trouble here is there are not many about so not as easy as it seems.
Who in their right mind spends 40k on mods then sells the car for half that price unless it’s a pain in the arse!
Luckily most of us value the cars better so don’t give them away for stupid money, ok if you find that fool I suppose but hardly supports the brand but hey a bargains a bargain.

[450Nick]

Because you enjoy doing it! I spent plenty building mine and loved the process of building and refining it as much as I did driving it. I never intended to sell mine but the build it right build it once mentality came in and I decided to start from a clean sheet and build a new one from scratch with a new chassis etc. I know full well that it won't be worth what I put into it if I ever decide to sell it (currently I do not), but I've so far spent 3 years working away and the car is still in pieces. I've had a great time with my hobby in that time though and am loving the challenge of design, solving problems, learning new skills and taking each idea from design through to a finished piece. That said I can't wait to drive it too, but that's not the only aspect to ownership - it's a hobby and I love it

Regarding the supercharger, if you like a project and want a fast TVR that makes you smile then go for it. If you don't then buy one that's already been done and just enjoy the driving part

Edited by 450Nick on Friday 25th June 08:20