1600 240 bhp and no charging!

[MX-5 Lazza]

Got a link to the thread? It could be a good one for PH'ers to have a look/laugh at

[trackerjack]

I may do Mr Lazza but I have a problem with PH in as much as the main forum is frequented by a complete bunch of twerps who are not even enthusiasts and I dont want them infecting what is actually a rather nice forum apart from one misguided fellow.
However I would add that you guys on this part are fine as is all the specialised parts of PH.

[identti]

My 1600 MX5 is on cams, throttle bodies, custom exhaust manifold and mapped properly (full rebuild in 2005 too) and it makes 130bhp at the flywheel. So at least 100bhp off.

Apparently if I ditched the restrictive HKS Silent HiPower exhaust I might get 135bhp....

[DVandrews]

Cam choice will make a huge difference to the output and characteristics of the engine, if you are only making 130BHP then it's likely that the duration and lift of the cams is pretty conservative. Lifting the head , fully porting it with possibly larger valves, springs that will take more lift and some more radical cams would probably see another 30-40BHP. The question would be whether the bottom end components are up to the job. Getting some more power isnt' too difficult, ensuring the engine stays in one piece just might be.

Dave

[rdodger]

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

How much does his 5 weigh? 550kg? He must only have half a car!

[PugwasHDJ80]

hmm depends what he spent

friend runs a WRC spec Super1600 Fiesta rally car.

It makes 219.9bhp at the wheels.

transmission losses even with a straight cut sequential box would suggest it was making 240bhp at the flywheel (in a car weighing ~900kg and geared to 110mph)

BUT this engine cost getting onto 20k- H-beam rods, ali crank (with a 1-2-3-4 firing order), massively long inlet tract, throttle bodies, lightened, properly flowed, balanced to rac spec, race pistons, v high comp ratio (would only run on 101 fia fuel), specific cam.

Revs to 10k ish, doesn't idle, and has bugger all torque.

but wind it up and it flies.

ask him how much he's spent, and who built the engine?

[skinny]

PugwasHDJ80 said:

this engine cost getting onto 20k- H-beam rods, ali crank (with a 1-2-3-4 firing order), massively long inlet tract, throttle bodies, lightened, properly flowed, balanced to rac spec, race pistons, v high comp ratio (would only run on 101 fia fuel), specific cam.

are you sure it's got a 1-2-3-4 firing order? that requires cylinders 1&3, and 2&4 going together, which would make pretty horrible vibrations...

Edited by skinny on Wednesday 5th October 17:27

[Adam205]

skinny said:

are you sure it's got a 1-2-3-4 firing order? that requires cylinders 1&3, and 2&4 going together, which would make pretty horrible vibrations...

Edited by skinny on Wednesday 5th October 17:27

+ ali crank LOL

[DVandrews]

No in line crank would survive a 1234 firing order 1342 or 1432 are the two usual orders.

Dave

[PugwasHDJ80]

DVandrews said:

No in line crank would survive a 1234 firing order 1342 or 1432 are the two usual orders.

Dave

go and look at the homologation papers of a fiesta super 1600

they all had that firing order

and yes it was horrible, and yes it did break things ALL The time (it shook the radiator to bits in one event)

[youngsyr]

Is the engine size still 1600cc, or is that what he started with? For an 1800cc, but you get my drift:

http://www.flyinmiata.com/index.php?deptid=4530&am...

Also, what fuel is he running the engine on?

[Mr Jenks]

DVandrews said:

No in line crank would survive a 1234 firing order 1342 or 1432 are the two usual orders.

Dave

Surely 1432 is the same as 1234 but the other way round.

I guess you meant to say 1342 or 1243 ?

[skinny]

yeah 1432 is messed up too...

[trackerjack]

I have asked the question gentlemen, but I would not normally bother because I have come across so many bull merchants its best to ignore them.
We shall see if there is an answer to the questions set below.


(Well you have gone quiet on this, what are you going to do?
I have a turbo'd MX5 and would not expect it to get any where near your power claims.
Perhaps you could enlighten me.
Did you build the engine?
What is the full spec?
I think more than 170 bhp with conventional tuning would be the limit.
Have you got the printout?
Forgive my scepticism but I am older than most and have heard many a tall tail.
Jon)

[Petrolhead]

DVandrews said:

Cam choice will make a huge difference to the output and characteristics of the engine, if you are only making 130BHP then it's likely that the duration and lift of the cams is pretty conservative. Lifting the head , fully porting it with possibly larger valves, springs that will take more lift and some more radical cams would probably see another 30-40BHP. The question would be whether the bottom end components are up to the job. Getting some more power isnt' too difficult, ensuring the engine stays in one piece just might be.

Dave

Hi Dave

Just thinking about the 1600 engine, my understanding the this is the same engine used in the 323 Turbo rally car?

If so would you not think the buttom end to be strong enough for 200BHP?

[youngsyr]

Petrolhead said:

DVandrews said:

Cam choice will make a huge difference to the output and characteristics of the engine, if you are only making 130BHP then it's likely that the duration and lift of the cams is pretty conservative. Lifting the head , fully porting it with possibly larger valves, springs that will take more lift and some more radical cams would probably see another 30-40BHP. The question would be whether the bottom end components are up to the job. Getting some more power isnt' too difficult, ensuring the engine stays in one piece just might be.

Dave

Hi Dave

Just thinking about the 1600 engine, my understanding the this is the same engine used in the 323 Turbo rally car?

If so would you not think the buttom end to be strong enough for 200BHP?

It's widely accepted that the bottom end is strong enough for 200 bhp and considerably more, but there are different ways of getting to 200 bhp.

I think Dave is suggesting that you would have to stress an NA car (rev its tits off, bore, stroke, etc) to make the kind of power that is being suggested, so you're putting a lot of stress on it that wouldn't be present by getting to 200 bhp using a turbo, etc.

[DVandrews]

Durability may not extend to the sort of RPM required to see 200BHP, some quick calcs will reveal how high the engine would have to rev to make 200BHP from 1600cc. As a rule of thumb, race engines derived from a production base struggle to make more than 90lb/ft per litre, so being generous, peak torque would be no more then 1.6 * 90 = 144lb/ft. Generally engines make their peak power when torque is around 90% of maximum, so 144 * .90 = 130lb/ft (give or take), BHP is a function of torque * RPM and at 5252 BHP and torque are equal, so to make 200BHP we need 200/130 * 5252 = 8080RPM.

Dave

Edited by DVandrews on Thursday 13th October 19:16

[trackerjack]

I think he was a troll.
Although it was on a Triumph forum there was enough there to burst his bubble and I got no reply so I expect just the usual my Fiesta does 130 type of bore.

It is amazing that whatever group of car nuts your associated with there is always a band of MX nuts too, probaly want something reliable to go with their old other classics.

[PugwasHDJ80]

DVandrews said:

Durability may not extend to the sort of RPM required to see 200BHP, some quick calcs will reveal how high the engine would have to rev to make 200BHP from 1600cc. As a rule of thumb, race engines derived from a production base struggle to make more than 90lb/ft per litre, so being generous, peak torque would be no more then 1.6 * 90 = 144lb/ft. Generally engines make their peak power when torque is around 90% of maximum, so 144 * .90 = 130lb/ft (give or take), BHP is a function of torque * RPM and at 5252 BHP and torque are equal, so to make 200BHP we need 200/130 * 5252 = 8080RPM.

Dave

Edited by DVandrews on Thursday 13th October 19:16

which is why the fiesta s1600 engine revs to just below 10k.....

[zxc23]

The UK 1600 mk1 race cars are getting 145hp (flywheel) with just a standard skimed head, recut valve seats, 0.5 stock pistons, advanced ignition timing and some tuning of the air mass.

So with big cams and throttle bodies 180-200 would be feasible.