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Which Engine To Choose From?
turboshmurbo - 22/7/10 at 08:28 AM

Hi there i am currently deciding weather to put a bike engine or car engine in to my Tiger.

I was all set on a bec until i spoke to someone getting low 14's on a quater of a mile. Is it me or is that underperforming, maybe i just expected more from a R1 kitcar.

So now i am contemplating putting a Zetec turbo engine in as i have a few parts lying round to build one.

which one would be best?.


balidey - 22/7/10 at 08:34 AM

1/4 mile times are not the be all and end all of performance. It depends what you want out of the car. Fast road / track days / drag strip.
Also budget. You can get any engine to give you whatever time you want down the 1/4 mile regardless of whether it came from a car or bike.


iank - 22/7/10 at 08:43 AM

Drag times for a BEC (well any car really) will depend very much on the diff ratio fitted. A 7 isn't really ideal for drag racing as while it's very low weight there's not enough over the driven wheels to get an exceptional time (though it will still beat 99% of 'normal' road legal cars.
A turbo/supercharger/NOS is the tool for a drag strip IMO.

See here for some representative times
http://www.locostbuilders.co.uk/viewthread.php?tid=58456 (hellfire's post)

BECs work best when you're 'on it' shifting up and down like a demon and spending a lot of time on twisty roads/tracks.


[Edited on 22/7/10 by iank]


loggyboy - 22/7/10 at 09:29 AM

There was a post a few days ago with a chap getting mid to low 13s in an R1 Mk.
even FWD tin tops with 150-200 brake can manage high 13s and low 14s so I would suggest the person you talked to cant Drag very well.


GBaggott - 22/7/10 at 10:43 AM

My friend with a fireblade fury (919) manages 12.9s a busa or zx14 would be about 12.0.
Its all about corner speed and sequential box in BECs.


adithorp - 22/7/10 at 10:57 AM

Ohhh... that's a big can of worms to open!

The CEC v BEC argument has been done to death on here. So expect very polarised views to energe.

If all you want is quick 1/4mile times then thats not a BEC's strongest point. In fact it's not the point of a BEC at all. I'm not saying it won't do it, just it's not the point. A BEC will give you between 300-400bhp/tonne which is achievable with a CEC but it also gives you less weight overall. That means it stops quicker and changes direction quicker. So add in the sequential gearbox and on anything twisty, it'll be hard work to keep up in a CEC (if the BEC is really going for it).

Down sides...
Lower torque, so not as easy to get off the line (hence the 1/4mile).
High revs aren't to everyones taste.
Reverse issue.
Extra weight (ie passenger) has more effect than in a heavier car.

adrian


big_l - 22/7/10 at 10:59 AM

i beg to differ on the 150 bhp to 200bhp tin tops getting into the high 13s

a had a 270bhp saxo vts on noz and it would go no faster than 14.0 @101mph

my s3 is running close tom 300 bhp and is still only 14.0 @98 mph

a std civic typoe r will do the pod in about 14.8

2004 m3 is about 13.8

s2000 is 14.5

golf r32 14.4

have no experience in kit cars as aint ever 1/4 miled mine yet lol

but done loads with tin tops!!


tomgregory2000 - 22/7/10 at 11:22 AM

revs and seq box is no substitue for a TURBO


loggyboy - 22/7/10 at 11:47 AM

quote:
Originally posted by big_l
i beg to differ on the 150 bhp to 200bhp tin tops getting into the high 13s

a had a 270bhp saxo vts on noz and it would go no faster than 14.0 @101mph

my s3 is running close tom 300 bhp and is still only 14.0 @98 mph

a std civic typoe r will do the pod in about 14.8

2004 m3 is about 13.8

s2000 is 14.5

golf r32 14.4



My redtopped nova did 14.089 (standard engine, albeit a highpower runner, but still only 143bhp at wheels). I also expected to get in to the 13s as the 60ft time on the 14sec run was attorcious(sp), sadly i never got a chance to run it again.
Admitildy it was stripped but still weighed it at about 750kg so I would expect a RWD car with similar or better power to weight to achieve better.

http://www.youtube.com/watch?v=WX-BR2WWQeo

If the best you could get out of 270 bhp saxo was a 14 then I would suggest either your figures are exagerated, or some more practice up the pod!!

[Edited on 22/7/10 by loggyboy]


MikeFellows - 22/7/10 at 01:14 PM

im building a BEC so heres my unbiased opinion.

if you want something for track, thats harsh and a little bit hardcore you build a BEC.

if you want something easy to bumble along in and potter down country roads without having to shift too much and going a little deaf, you build a CEC

thats not to say one is better than the other, I just think a BEC is a little more race car orientated.


chris mason - 22/7/10 at 01:28 PM

From your 2 choices (R1 v Zetec Turbo)

If you want outright top speed then it has to be the Zetec Turbo

If you want a cheap sequential box it has to be the R1

If you want the fastest laptime then that's open to debate i'd say Zetec Turbo

If you want the cheapest option then it has to be R1

I'm sure you can see where this is going, it's down to what you want the car for, it's a subject that's being covered many times and still there is no ONE answer.

I've had 4 different bike engines in cars and 2 car engines, if i built another it would have a car engine it again


Werner Van Loock - 22/7/10 at 05:09 PM

quote:
Originally posted by chris mason
From your 2 choices (R1 v Zetec Turbo)

If you want outright top speed then it has to be the Zetec Turbo

If you want a cheap sequential box it has to be the R1

If you want the fastest laptime then that's open to debate i'd say Zetec Turbo

If you want the cheapest option then it has to be R1

I'm sure you can see where this is going, it's down to what you want the car for, it's a subject that's being covered many times and still there is no ONE answer.

I've had 4 different bike engines in cars and 2 car engines, if i built another it would have a car engine it again


Result, get in the middle and get a 4age, possibly with a rotrex charger.


RAYLEE29 - 22/7/10 at 08:14 PM

horses for courses really but the main point of sevenesque cars is cornering ability not drag racing.
if your serious about 1/4 mile times build a rail car.
if you want a good allrounder for just you then bec, if you want to take a passenger and not lose too much performance then cec.
all just my opinion of course.
Ray

[Edited on 22/7/10 by RAYLEE29]


dlatch - 22/7/10 at 10:34 PM

quote:
Originally posted by RAYLEE29
if you want a good allrounder for just you then bec, if you want to take a passenger and not lose too much performance then cec.



could always befriend a really skinny guy/gal and keep with the bec

would be interested in what time a throttle bodied 2.0 zetec does the 1/4 in though will run mine one day to find out


Rocket_Rabbit - 22/7/10 at 10:45 PM

quote:
Originally posted by RAYLEE29
if you want a good allrounder for just you then bec, if you want to take a passenger and not lose too much performance then cec.

I fail to see how you are making this conclusion.

If you say it's because of torque, I will beat you with a stick making sure to apply a perpendicular force