1600 240 bhp and no charging!

[trackerjack]

On another forum a guy reckons with race cams and throttle bodies on a 1600 MX5 lump he was showing 240 bhp. Now I think this is up with the fairies cos race cams would not suit the road and I would imagine about 180 bhp would be the best one of these engines could achieve.
Over to you guys before I call his bluff.
Is it possible?

[The Moose]

It's possible to hook up a rolling road to show basically any figure you like. I don't quite understand it myself...but apparently you can

[MX7]

trackerjack said:

I think this is up with the fairies

I think you're being very polite. He's claiming he's doubled the power!

[Johnboy Mac]

N/a 240bhp road engine, no way. 240bhp full race engine I suspect is possible with rebuilds very few hundred miles. But very happy to be proved wrong.

[Richyvrlimited]

You mate is living in cloud cookoo land

[paul99]

A friend of mine spent upwards of £10K on his 1.8 MK2 engine to get ~210BHP and that had the complete works (IRTB'S, Forged crank, pistons, head etc) done on it by a race car engine builder.

So he is definitely talking out of his arse.

[tuttle]

Agreed, pure arse seepage! You will never get that sort of increase from an NA engine, & believe me I've tried. Big shot of N2O might do it though

[Oxygen2k10]

Have a look on MX5Nutz for Skuzzle*. He's spent a rather hefty amount of time and money on his engine, it's running higher compression, throttle bodies, standalone ecu, rev limit raised to 9000 and more and yet he's only managed to achieve about 160(ish)bhp.

240bhp on a road going motor sounds pretty farfetched if you ask me.

• For some reason I cant get on the site at the mo to grab all the info

[skinny]

from a 1.6? impossible unless you're spinning it at 15,000rpm perhaps

[DVandrews]

It's not impossible, just highly unlikely.

BHP is a function of torque and RPM. I have a bullst busting spreadsheet that gives the minimum RPM necessary to make a given level of HP from an engine of known size.

Any production based engine will struggle to make more than 90lb/ft per litre regardless of the level of development, peak power is generally made when torque is at around 90-95% of it's maximum. If you do the maths then a 1600 would have to *peak* at a minimum of 9200RPM to make 240BHP, that's if everything were perfect.

The best I have seen from a production based 1600 is 225BHP and this was peaking at 9300RPM. This was acheived with a lot of cam, mega headwork with very large ports & valves , semi downdraughting of the in let ports and a lot of development time. It was a square engine 80x80.

Given the limited bore size and therefore valve area I expect you would hit the wall at around 230BHP on a 1600 MX5 engine.

Dave

[Johnboy Mac]

DVandrews said:

Given the limited bore size and therefore valve area I expect you would hit the wall at around 230BHP on a 1600 MX5 engine.

Dave

Dave, approx how much would you reckon to build?

J.

[roddo]

Richyvrlimited said:

You mate is living in cloud cookoo land

IF its true I'll buy it.............

But as richy said........................ Cloud cookoo

[DVandrews]

Johnboy Mac said:

Dave, approx how much would you reckon to build?

J.

If you factor in a steel crank, rods and forged pistons, that would be around 3.5-4K in basic parts alone, add another 5-6K for TBs,manifold, ex manifold, airbox, big valves, head inserts, porting, ECU, cams, springs, caps, verniers, balancing, lightweight flywheel, building etc.

I'd say 10K would see it done.

Dave

[attym3]

tuttle said:

Agreed, pure arse seepage!

I agree with this.

[Johnboy Mac]

DVandrews said:

If you factor in a steel crank, rods and forged pistons, that would be around 3.5-4K in basic parts alone, add another 5-6K for TBs,manifold, ex manifold, airbox, big valves, head inserts, porting, ECU, cams, springs, caps, verniers, balancing, lightweight flywheel, building etc.

I'd say 10K would see it done.

Dave

Thanks for the reply Dave, not surpised at ten grand figure.

[trackerjack]

Ha ha so I am not alone with my doubt then as it seems like a complete sweep of no's
My Quantum 2+2 RST was advertised as making 240 bhp but I did not believe it or even argue with the seller as it does have about 170 or so which is enough to send it torque steering up the road and any more would be too much for me.
I have been an angler and petrolhead and both these fields seem to breed liars and as an engineer I am a stickler for facts.
I will lurk on the other forum to see what other nonsense comes out before I wade in with some derision.

[MX-5 Lazza]

If you need someone to give a less negative reply, I'll give it a go...
Maybe what he meant to say was that it had 240bhp per ton. Still not likely but much more plausible

[DVandrews]

MX-5 Lazza said:

If you need someone to give a less negative reply, I'll give it a go...
Maybe what he meant to say was that it had 240bhp per ton. Still not likely but much more plausible

With respect my reply was realistic rather than negative.

Dave

[MX-5 Lazza]

DVandrews said:

MX-5 Lazza said:

If you need someone to give a less negative reply, I'll give it a go...
Maybe what he meant to say was that it had 240bhp per ton. Still not likely but much more plausible

With respect my reply was realistic rather than negative.

Dave

I didn't really mean the replies were negative, just that the result of the replies was negative i.e. that the guy is probably talking out of his arse

[trackerjack]

I was being nice for a change and merely wrote that I thought Walter Mitty died with Danny Kaye (younger forumers had better ask a wrinkly)!