Bike power vs. Car power
Discussion
Hi guys,
Firstly, I know there has been a similar question asked previously but my queory is slightly different.
Right, I want to build a kit car strictly for the track but lap times are very important to me. Providing power is the same - which ever route I take I will be turbocharging to 200bhp - would I be better off with a bike engine (1000cc) or a car engine (2000cc)?
I quite like the idea of the higher revs and continuous power delivery of the bike engine but my main concerns are the lower torque of the bike engine vs. The extra weight of the car engine. The car will be set up properly for the track ofcourse.
Thanks in advance guys, all friendly opinions are welcome!
Firstly, I know there has been a similar question asked previously but my queory is slightly different.
Right, I want to build a kit car strictly for the track but lap times are very important to me. Providing power is the same - which ever route I take I will be turbocharging to 200bhp - would I be better off with a bike engine (1000cc) or a car engine (2000cc)?
I quite like the idea of the higher revs and continuous power delivery of the bike engine but my main concerns are the lower torque of the bike engine vs. The extra weight of the car engine. The car will be set up properly for the track ofcourse.
Thanks in advance guys, all friendly opinions are welcome!
In before the debate heats up, with three obvious questions:
1) Why turbo charge? 2 litre NA can easily get you to 200bhp and beyond, with none of the power delivery or thermal issues associated with turbos...
2) Do you have any ideas about which style of car you're likely to be going for?
3) Why 200bhp? Is it a class limit you're aiming for... if not, could thinking in pwr/weight terms be helpful given the differences between engine types?
1) Why turbo charge? 2 litre NA can easily get you to 200bhp and beyond, with none of the power delivery or thermal issues associated with turbos...
2) Do you have any ideas about which style of car you're likely to be going for?
3) Why 200bhp? Is it a class limit you're aiming for... if not, could thinking in pwr/weight terms be helpful given the differences between engine types?
Given your criteria, bike engine wins hands down, provided the rest of the car suits the engine installation (ie. lightweight).
But as LooneyTunes says, if you're only aiming for 200bhp from a turbo 2 litre on such an obviously track orientated car, there's something wrong. A bog-standard VAG 2-litre TSi will give you more than that.
But as LooneyTunes says, if you're only aiming for 200bhp from a turbo 2 litre on such an obviously track orientated car, there's something wrong. A bog-standard VAG 2-litre TSi will give you more than that.
Hi guys, 200bhp was to provide the required power to weight ratio. The car will be approx 800kg.
Good point about the turbo. The 2.0 zetec provides 130bhp standard, about the same as the older (cheaper) bike engines. Turbocharging seems to give more bang for your buck, at least where bike engines are concerned? Small increases in boost will always provide more power aswell.
That's the logic behind my thinking but do correct me if I'm wrong.
Good point about the turbo. The 2.0 zetec provides 130bhp standard, about the same as the older (cheaper) bike engines. Turbocharging seems to give more bang for your buck, at least where bike engines are concerned? Small increases in boost will always provide more power aswell.
That's the logic behind my thinking but do correct me if I'm wrong.
FastfordRog said:
Hi guys, 200bhp was to provide the required power to weight ratio. The car will be approx 800kg.
Good point about the turbo. The 2.0 zetec provides 130bhp standard, about the same as the older (cheaper) bike engines. Turbocharging seems to give more bang for your buck, at least where bike engines are concerned? Small increases in boost will always provide more power aswell.
That's the logic behind my thinking but do correct me if I'm wrong.
Oh, and the reason behind the zetec was it's low price and availability.Good point about the turbo. The 2.0 zetec provides 130bhp standard, about the same as the older (cheaper) bike engines. Turbocharging seems to give more bang for your buck, at least where bike engines are concerned? Small increases in boost will always provide more power aswell.
That's the logic behind my thinking but do correct me if I'm wrong.
For pure track, I would have probably leant towards v lightweight and bike engine, but agree that at 800kgs seems heavy (btw what is it you're thinking of building?). I know some people do run at that sort of weight though.
Of course, one consideration has to be ease of keeping it running. Blow a bike engine and a quick eBay will see you with another (some people seem to treat them as £1000 disposable units). Different story with car engine where good chunk of the cost will have been related to tuning.
Have you looked at things like Vaxhall redtops? SBD do some kits that quite easily make 200bhp+
Of course, one consideration has to be ease of keeping it running. Blow a bike engine and a quick eBay will see you with another (some people seem to treat them as £1000 disposable units). Different story with car engine where good chunk of the cost will have been related to tuning.
Have you looked at things like Vaxhall redtops? SBD do some kits that quite easily make 200bhp+
Edited by LooneyTunes on Saturday 27th August 19:31
200Plus Club said:
you can get a crate zetec brand new short motor for about 800 quid. my friends cost 400 quid from a mondeo, and made 180bhp on throttle bodies and DTA, while bog stock. with some minor headwork and cam it made 200bhp reliably, and is still going strong on track.
Cheers mate, looking like I wont really need a turbo if I choose the 2.0 then.FastfordRog said:
If I go the car route then yes it will either be the zetec or red top, will do some research on those kits!
I want to strip my XR2i and build a track toy, preferably rear (bike) engined, rwd. I know it's a big project to embark on but that's mostly the point lol.
Sounds like fun. I want to strip my XR2i and build a track toy, preferably rear (bike) engined, rwd. I know it's a big project to embark on but that's mostly the point lol.
Assume you've had a look at the likes of Z-cars to get an idea of the way some of the conversions can work - personally I really like their Mini conversions.
FastfordRog said:
The car will be approx 800kg.
Your basic numbers aren't making sense... just as 200bhp from a turbo 2 litre track engine is woefully pessimistic, so is 800 kilos for a BEC.If you're buildng a BEC for track use, you should be aiming at <550 kilos... <450 if you're really serious. Though not with an XR2 bodyshell of course; that's why my original post suggestes that the car would need to be lightweight enough to match the engine. You need to give us the full story, if you want decent advice: internet forums are like computers generally - garbage in = garbage out.
You told us that you were thinking of building a kit car not re-engining a heavy steel production car bodyshell.
I agree with Nedz that if you're genuinely anticipating an 800 kilo car, then a bike engine would be the wrong choice; it lacks torque and you'll kill the transmission in no time flat.
Have a look at this thread on the Locost forum to get some idea of real-world weights for BECS.
And while you're there, you may wish to have a good look at the other threads on the forum to get some idea of the reliability issues around bike engines in cars: best to go in with your eyes wide open. The 'if I blow it up, another is only £1000 on e-bay' argument makes sense until you have to part with £1000 every few thousand miles, whereas the aforementioned VAG 200bhp TSi is seeing service in millions of cars at the sort of mileages you'd be unlikely to rack up in a kit car in several lifetimes.
Edited by Sam_68 on Sunday 28th August 08:16
Just a bit, yes. Impossible in fact.
If he'd given us the full story originally, my initial advice would have been diametrically opposite: an 800kg BEC engined track car would be a dead loss.
It's never going to be the quickest thing around a circuit, anyway, but if I was looking at a mid-engined conversion of an XR2, I think I'd go for a reasonably torquey N/A multi-cylinder. Alfa V6 would be nice...
If he'd given us the full story originally, my initial advice would have been diametrically opposite: an 800kg BEC engined track car would be a dead loss.
It's never going to be the quickest thing around a circuit, anyway, but if I was looking at a mid-engined conversion of an XR2, I think I'd go for a reasonably torquey N/A multi-cylinder. Alfa V6 would be nice...
As an aside it would help if state whether you're going to race or just do tds. If you're just going todo tds then lap times are irrelevant for two reasons:
Firts, timing is prohibited and second a very fast car limits where you can enjoy the car - you spend most of the day waiting to overtake instead of enjoying yourself.
There is also a further consideration in that cars that deliver the truly fast laps employ downforce are much less enjoyable to drive for many. Back to back i found the xtr2 much faster than the mega cars but just not as fun to drive.
Firts, timing is prohibited and second a very fast car limits where you can enjoy the car - you spend most of the day waiting to overtake instead of enjoying yourself.
There is also a further consideration in that cars that deliver the truly fast laps employ downforce are much less enjoyable to drive for many. Back to back i found the xtr2 much faster than the mega cars but just not as fun to drive.
Gassing Station | Kit Cars | Top of Page | What's New | My Stuff