Engine choice for 400bhp/ton in a 7?
Discussion
Hi all, I am considering something like an MK Indy for my next project, and after reading up on the BEC market I thought something like an R1 engine would be ideal - high revs, super low weight, ideal for track fun and pretty reliable. I know everyone says that they're ballistically fast, but doing the maths, 160 bhp to push a 450kg car plus an 80kg driver only works out at 300bhp/ton. My Supra is a totally different car, but that makes an easy 350bhp/ton with four seats, air con and a stereo! Although a seven would feel faster, and be geared more for 0-100mph acceleration, I definitely don't want to go backwards (or even stand still) in terms of speed - in fact I am pretty used to the Supra and would love a bit more power (or a lot less weight!).
With this in mind, what would be the ideal engine choice (almost certainly NA) to get 400bhp/ton or over in a 7? Are there any bike engines that make 220ish bhp? Failing that, I would be looking at a car engine, giving an all-up weight of around 600kg I guess, that makes about 250bhp NA which is going some from a small I4 lump.
I want to try and avoid some highly strung, fully rebuilt race engine crammed full of expensive parts as I wouldn't dare thrash the bejeezus out of it on a track for fear of breaking it - a reliable unit running factory bhp would be my preferred choice. What do Caterham use for their R400 for example?
With this in mind, what would be the ideal engine choice (almost certainly NA) to get 400bhp/ton or over in a 7? Are there any bike engines that make 220ish bhp? Failing that, I would be looking at a car engine, giving an all-up weight of around 600kg I guess, that makes about 250bhp NA which is going some from a small I4 lump.
I want to try and avoid some highly strung, fully rebuilt race engine crammed full of expensive parts as I wouldn't dare thrash the bejeezus out of it on a track for fear of breaking it - a reliable unit running factory bhp would be my preferred choice. What do Caterham use for their R400 for example?
Edited by aww999 on Tuesday 28th April 18:08
Have you been in a BEC yet? I've managed to impress my biker mates with mine. I have about 270 bhp/ton with me in the car and I find it to be plenty more than enough on the back roads that I drive on. I can beat my mate's 700 Monster down the twisty roads too.
However, if you want a genuine 400 bhp/ton, then the best bet with a near stock engine will be the S2000 lump and box.
However, if you want a genuine 400 bhp/ton, then the best bet with a near stock engine will be the S2000 lump and box.
Suggest you ride in a CAR with a bike engine as im sure it will show the supa round any technical track, the bike engine is much more nuetral around any corner to the point you can shift when it just would not be possible in a heavier can engined car. BHP per Ton does not always mean its the fastest its how the package works. I am sure you would be very impresed with a fireblade in a very well set up MK.
You clearly have not been out in a decent Kit car before judging by your comment. Get a ride in one.
An MK with an R1 is about 460kg and 150bhp, that gives about 326 bhp/ton. You could put a Busa in there and that would give you about 382 bhp/ton (and thats a rough 10kg of extra weight accounted for). You don't have to measure yourself in the car to get its bhp/ton.
But any of these are savage and much more capable than the figure suggests. Forget what your Supra is running, even a 120bhp Blade would be a different league.
I do see in your profile the Supra is running 450bhp though, so with a 1600kg weight that is 280bhp/ton. But it is meaningless to an extent as I say, with a kit car you can brake later, turn in faster, exit faster, get on the power earlier and come out at a much higher speed, and being light they can also stay out and do lap after lap after lap unlike heavier cars.
An MK with an R1 is about 460kg and 150bhp, that gives about 326 bhp/ton. You could put a Busa in there and that would give you about 382 bhp/ton (and thats a rough 10kg of extra weight accounted for). You don't have to measure yourself in the car to get its bhp/ton.
But any of these are savage and much more capable than the figure suggests. Forget what your Supra is running, even a 120bhp Blade would be a different league.
I do see in your profile the Supra is running 450bhp though, so with a 1600kg weight that is 280bhp/ton. But it is meaningless to an extent as I say, with a kit car you can brake later, turn in faster, exit faster, get on the power earlier and come out at a much higher speed, and being light they can also stay out and do lap after lap after lap unlike heavier cars.
Edited by matt frost on Tuesday 28th April 09:43
Edited by matt frost on Tuesday 28th April 09:43
Thanks for the responses guys. I understand the handling prowess (cornering speeds, braking distances etc) will be far greater than my heavy old supra, and this is a big part of the appeal of a lightweight kit car. However, I don't want to sacrifice the acceleration I get at the moment - datalogs show 0-100mph in 8.8 seconds even with plenty of wheelspin, that's on the latest "civilised" setup, so I think it's still north of 500bhp. What kind of 0-100 times does a BEC do?
I deliberately included the driver weight in my sums because it makes such a huge difference in power/weight in such a lightweight car, and the car won't be going anywhere without hauling me with it!
I guess BEC is still my most sensible choice without spending lots of cash on a trick XE or K-series. I also have a Mk1 MR2 with around 100bhp/ton, I have an absolute blast in that spinning the little 1.6 up to 7500rpm even though it's probably slower than most diesel hatches, so maybe I wouldn't miss the power that much . . .
I deliberately included the driver weight in my sums because it makes such a huge difference in power/weight in such a lightweight car, and the car won't be going anywhere without hauling me with it!
I guess BEC is still my most sensible choice without spending lots of cash on a trick XE or K-series. I also have a Mk1 MR2 with around 100bhp/ton, I have an absolute blast in that spinning the little 1.6 up to 7500rpm even though it's probably slower than most diesel hatches, so maybe I wouldn't miss the power that much . . .
beware of wild claims when it come to 0-100mph times, it was said for a long time that bec 7's do it in 8 seconds yet at every drag day i've done they've struggled to get to 100mph in 13 seconds, some of the smaller 7's do it a bit faster but still not as quick as your supra. Becs are all about cornering and braking not out right pace, if you want a faster 7 you need to be looking at 250bhp+ car engines.
Edited by indy2000 on Tuesday 28th April 18:35
I used to own a supra with basic mods to about 400 bhp, it was a good car and the power was great but compared to my kit car its not a patch. Not wanting to start the BEC CEC argument again but mines a CEC. I own a big bike but never driven a BEC, the only CEC that has ever come near me on track was a Hyabusa Turbo Dax Rush and that was on my first outing in the car before my new turbo and sticky tyres.
It sounds to me like you may be better off with a CEC with circa 250 bhp to keep you happy. I would go for something turbo charged so you can go up in power if you like without costing you a fortune. Any BEC or NA car engine is going to be very expensive to mod above 200 bhp. A honda S2000 would be a good option but not cheap at £2500 for a 2nd hand set up.
Something like nissan 200, cossie or even an rx7 all make very good options for big power.
The fact that you own a supra gives me the impression that you are more concerned with straight line power which a stock BEC just wont give you. If it is handling liek nothing on earth then go for a BEC.
All just IMHO of course.
It sounds to me like you may be better off with a CEC with circa 250 bhp to keep you happy. I would go for something turbo charged so you can go up in power if you like without costing you a fortune. Any BEC or NA car engine is going to be very expensive to mod above 200 bhp. A honda S2000 would be a good option but not cheap at £2500 for a 2nd hand set up.
Something like nissan 200, cossie or even an rx7 all make very good options for big power.
The fact that you own a supra gives me the impression that you are more concerned with straight line power which a stock BEC just wont give you. If it is handling liek nothing on earth then go for a BEC.
All just IMHO of course.
I have a 180-bhp duratec in my westy - it is quicker in a straight line than a 911 turbo (I know this after one trying to get away from me the other day - it just couldnt shake me especially on the corners)
Ok after 80 mph areodynamics start to get the better of this type of car, but it has to be said in general road driving they are much much quicker than virtually every type of car, purely down to the speed you can carry around the corners and how quickly you can get the power down on the straights
So a duratec with 230bhp (reasonably cheap to spec up to that level - strengthen bottom end, piston change, ported head and cams with throttle bodies should easily get you 230bhp plus) is gonna be a lightening machine and we all know how quick the caterham R500 is with 250bhp
Bike engines a bit too fragile for my liking
Ok after 80 mph areodynamics start to get the better of this type of car, but it has to be said in general road driving they are much much quicker than virtually every type of car, purely down to the speed you can carry around the corners and how quickly you can get the power down on the straights
So a duratec with 230bhp (reasonably cheap to spec up to that level - strengthen bottom end, piston change, ported head and cams with throttle bodies should easily get you 230bhp plus) is gonna be a lightening machine and we all know how quick the caterham R500 is with 250bhp
Bike engines a bit too fragile for my liking
Hi, If it helps I have a Spire GTR with zx12r engine. I tracked it all season at Knockhill last year with no problems, bike engines are bullet proof if left standard but you will have to re build the gearbox every so often(not that exspensive) My car is set up well and the zx12 will have about 125bhp at the wheels but be assured it sticks with lamborgini gallardos, ferrari 360's down Knockhill straight, by the braking point we will be doing 120mph, around the corners it will eat most things. At this stage lap times are down to the driver more than the car I can tell you I'm a good driver but in the right hands my car could probably be 2 seconds faster round the track.
The zx12 is kawasaki comparison to the busa, but there is know a zx14 (my next purchase)if you want to go for it; my advise forget about bhp per tonne get a powerfull engine and concentrate your time money and effort on handling and brakes, then trust me you'll have a car that will strech your driving skills behond your expectations.
Good luck,
craig
The zx12 is kawasaki comparison to the busa, but there is know a zx14 (my next purchase)if you want to go for it; my advise forget about bhp per tonne get a powerfull engine and concentrate your time money and effort on handling and brakes, then trust me you'll have a car that will strech your driving skills behond your expectations.
Good luck,
craig
cleggyWestfield said:
Ok after 80 mph areodynamics start to get the better of this type of car, but it has to be said in general road driving they are much much quicker than virtually every type of car, purely down to the speed you can carry around the corners and how quickly you can get the power down on the straights
I have often heard that aerodynamics hold back the 7 type cars. My regular journeys are all high speed duel carriage way type so how would the full bodies of the Fury/Stylus type cars fair? Does this style of body allow higher cruising speeds while still maintaining the cornering abilities?matt frost said:
You clearly have not been out in a decent Kit car before judging by your comment. Get a ride in one.
An MK with an R1 is about 460kg and 150bhp, that gives about 326 bhp/ton. You could put a Busa in there and that would give you about 382 bhp/ton (and thats a rough 10kg of extra weight accounted for). You don't have to measure yourself in the car to get its bhp/ton.
But any of these are savage and much more capable than the figure suggests. Forget what your Supra is running, even a 120bhp Blade would be a different league.
I do see in your profile the Supra is running 450bhp though, so with a 1600kg weight that is 280bhp/ton. But it is meaningless to an extent as I say, with a kit car you can brake later, turn in faster, exit faster, get on the power earlier and come out at a much higher speed, and being light they can also stay out and do lap after lap after lap unlike heavier cars.
A mate of mine has a R33 GTR running 404BHP at the crank on the dyno and he can really drive it. I have a MAC1 with a old 918 blade lump with little tuning it prob runs high 130's at the crank. Upto 80 he cant keep with me. 80 to 110 were even and anything above I get destroyed. These 7's has said several times are all about corners, brakes and acceleration. There about as aerodynamic as a brick once you hit 3 fig speedsAn MK with an R1 is about 460kg and 150bhp, that gives about 326 bhp/ton. You could put a Busa in there and that would give you about 382 bhp/ton (and thats a rough 10kg of extra weight accounted for). You don't have to measure yourself in the car to get its bhp/ton.
But any of these are savage and much more capable than the figure suggests. Forget what your Supra is running, even a 120bhp Blade would be a different league.
I do see in your profile the Supra is running 450bhp though, so with a 1600kg weight that is 280bhp/ton. But it is meaningless to an extent as I say, with a kit car you can brake later, turn in faster, exit faster, get on the power earlier and come out at a much higher speed, and being light they can also stay out and do lap after lap after lap unlike heavier cars.
Edited by matt frost on Tuesday 28th April 09:43
Edited by matt frost on Tuesday 28th April 09:43
Cant fault my bike engined kitcar its like owning a bike on 4 wheels. No engine/box reliability problems I can report. Will change end of year for a 1200/1400 as the 918 i have suffers with little torque
Ebo100 said:
cleggyWestfield said:
Ok after 80 mph areodynamics start to get the better of this type of car, but it has to be said in general road driving they are much much quicker than virtually every type of car, purely down to the speed you can carry around the corners and how quickly you can get the power down on the straights
I have often heard that aerodynamics hold back the 7 type cars. My regular journeys are all high speed duel carriage way type so how would the full bodies of the Fury/Stylus type cars fair? Does this style of body allow higher cruising speeds while still maintaining the cornering abilities?Has to be said the one he has just sold has the quickest car I have ever experianced with about 250-300bhp it was savage
cleggyWestfield said:
I have a 180-bhp duratec in my westy - it is quicker in a straight line than a 911 turbo (I know this after one trying to get away from me the other day - it just couldnt shake me especially on the corners)
The 911 Turbo wasnt trying. I have a 911 Turbo and I have also have a Westy with over DOUBLE your horsepower....911 Turbos are FAST cars mate.
ner ner... ner ner ner ... lol
anyway your missing the point, if you wanna go quick around a track or on the road you buy something that is very light and powerful (if you can afford a gt3 well you got the best of both worlds), doesnt matter if it is 7style or an aeon style car - point is there within more peoples budget and quicker than most things on a track day and if you do stick it into a crash barrier its gonna cost you a lot less to put right compared to writing of a 911 turbo
never said 911 turbos were slow, just said that my westy is quicker than the one I came across - and he was definately trying
anyway your missing the point, if you wanna go quick around a track or on the road you buy something that is very light and powerful (if you can afford a gt3 well you got the best of both worlds), doesnt matter if it is 7style or an aeon style car - point is there within more peoples budget and quicker than most things on a track day and if you do stick it into a crash barrier its gonna cost you a lot less to put right compared to writing of a 911 turbo
never said 911 turbos were slow, just said that my westy is quicker than the one I came across - and he was definately trying
Edited by cleggyWestfield on Wednesday 29th April 21:40
cleggyWestfield said:
ner ner... ner ner ner ... lol
anyway your missing the point, if you wanna go quick around a track or on the road you buy something that is very light and powerful (if you can afford a gt3 well you got the best of both worlds), doesnt matter if it is 7style or an aeon style car - point is there within more peoples budget and quicker than most things on a track day and if you do stick it into a crash barrier its gonna cost you a lot less to put right compared to writing of a 911 turbo
never said 911 turbos were slow, just said that my westy is quicker than the one I came across - and he was definately trying
Sorry mate there's no chance your car could keep up with any 911 Turbo on a straight. I don't own a 911 or never have done but have come across a few on track days and my Noble gtr,gtr zx12,exige 240 cup cant keep up; and all of those cars have left 7's with bike engines for dead down straights.anyway your missing the point, if you wanna go quick around a track or on the road you buy something that is very light and powerful (if you can afford a gt3 well you got the best of both worlds), doesnt matter if it is 7style or an aeon style car - point is there within more peoples budget and quicker than most things on a track day and if you do stick it into a crash barrier its gonna cost you a lot less to put right compared to writing of a 911 turbo
never said 911 turbos were slow, just said that my westy is quicker than the one I came across - and he was definately trying
Edited by cleggyWestfield on Wednesday 29th April 21:40
Don't get me wrong I love zx12 gtr its the best fun on the track i've ever had!!!! but all bike engined cars run out of legs after 80 ish so unless its a very short straight your dreaming mate...
read all my posts again ...arrgghh ... we are talking about what is quicker on the road/track ... go and have a look at any youtube video and see the caterhams and westies eating 911's inc std turbo's
when I said mine was quicker in a straight line, perhaps what I should of said is on the road/track due to previos reasons mentioned about weight and carrying speed through corners - I am already on the power and rattling up the straight whilst a 911 trundles around the bend and depending how long the straight is he may come past by the end of it but then he will probably be passed under braking
you have to ask yourself if you want a car that is quicker on the road or track or a car is quicker at santa pod
anyway nuff about 911 turbos and get back on subject
when I said mine was quicker in a straight line, perhaps what I should of said is on the road/track due to previos reasons mentioned about weight and carrying speed through corners - I am already on the power and rattling up the straight whilst a 911 trundles around the bend and depending how long the straight is he may come past by the end of it but then he will probably be passed under braking
you have to ask yourself if you want a car that is quicker on the road or track or a car is quicker at santa pod
anyway nuff about 911 turbos and get back on subject
Gassing Station | Kit Cars | Top of Page | What's New | My Stuff