10,000hp from the Top Fuel Hemi

Dave-R · Post by **Dave-R** » Thu Oct 10, 13 1:41 pm

Interesting about the firing order.

jerry · Post by **jerry** » Thu Oct 10, 13 4:07 pm

That is interesting about the firing order,would like some more info on whats
involved and how it makes more power but guess its all top secret.

Dave-R · Post by **Dave-R** » Thu Oct 10, 13 4:41 pm

Crank, cam and distributor (if used) would have to be custom made.

shovelheadrob · Post by **shovelheadrob** » Thu Oct 10, 13 7:06 pm

We've been running a 18736542 firing order on Badbird for a few years now it's just a different cam as the pistons are still in the same position relative to crankshaft rotation just that the power stroke becomes the intake stroke, same if you swap 2 & 3 around. It's nothing new, was used in pro stock a long time ago. Various theories out there about the logic behind it including harmonics & parasitic power losses. It's worth a small percentage of free power which when you are already extracting thousands of bhp which can be significant, for a street or even sub 1000bhp strip motor it would be an expensive waste of time.
Dave, you just swap the HT leads over (might have to buy new if they don't reach!)

Pete · Post by **Pete** » Thu Oct 10, 13 7:21 pm

Very useful, Rob

bratfink · Post by **bratfink** » Fri Oct 18, 13 2:49 pm

Regular car HP can be more effectively tuned by combining relective waves in the exhaust. That means tuning header pipe lengths and bend positions so as to interact with the ajoining pipes pulse waves at a specific time.

They cannot have changed the firing order in order to optimize reflective waves in the TFX since the exhust ports are all independant. Therefore it must be either a harmonic or force equalization issue to keep cranks alive longer under the extreme forces. I doubt the engne is making more power because of the change of firing order, I suspect the firing order has been changed to address an issue created by making that much power.

Dave-R · Post by **Dave-R** » Fri Oct 18, 13 5:16 pm

shovelheadrob wrote:Dave, you just swap the HT leads over (might have to buy new if they don't reach!)

Yeah realised that cock-up just after writing it while at work and then completely forgot to edit it after.

Just me going round the twist. Nothing new.

Guy · Post by **Guy** » Fri Oct 18, 13 6:12 pm

I'm with James on this cause he is far brainer than me.. and it sorter makes sence ...

Tweety · Post by **Tweety** » Fri Dec 06, 13 1:22 pm

Ah see Dave I leave for a few years and come back to find that absolutely nothing has changed..

Dave-R · Post by **Dave-R** » Fri Dec 06, 13 3:56 pm

Well I still have my looks and you don't have the hair.

Guy · Post by **Guy** » Fri Dec 06, 13 4:03 pm

Dave just for you mate

..

Dave-R · Post by **Dave-R** » Fri Dec 06, 13 4:06 pm

I said I still have my looks. I didn't say they were any good.

Tweety · Post by **Tweety** » Fri Dec 06, 13 5:14 pm

Ah Mr Robson I have soooooo missed our little chats! But on the subject of top Fuel I now know how John force won all those championships- very subtle and completely undetectable !

db · Post by db » Fri Dec 06, 13 5:56 pm

Hydrazine?
Nah, the green flames would have given the game away... come on then, spill!

Tweety · Post by **Tweety** » Fri Dec 06, 13 5:59 pm

funnily enough IF you are smart enough to put a catalyst in the exhaust the flame will match the other car and no one will be any the wiser...
Very very sneaky indeed. but no not hydrazine, you can't tamper with the fuel, it all happens inside the motor.. Private email on this one though sir !