yeah you are right they only held togeher for aronud 3 events, that is about 10 races. They would hold the motor on about 7500 - 7800rpm around the ring. there were some big durations used on the cam and they had around 560 thou total lift on them. makeing it breath is a big issue hence the 100mm TB and the 4" exhaust. The heads were huge i don't know what size the valves were but they did a serious amount of porting. The went to the extent of removing the valve guides in the bore to get more flow. it chewed thourgh valve stem seals but they had nothing better to do than work on the car anyway.

They had it down to an art though, it was a week turn around on there rebuilds.

It seems like the impossible hence why noone has a 4.0L that revs. To do it properly it costs BIG money. The bottom end for mine has cost $4200 so far. alot of people say it is a waist of money but anyone can put a turbo on them and make them go hard, the challange is in developing new technology in an engine. Thats wha i think anyway.

come on... what sort of power did they make???

as for the 160rwkw. My old engine made 158rwkw and all i did to that was a tighe 826A cam, crower 90lb springs, the head had 15thou off it and a ACL HI COMP head gasket fitted, chiptorque chip, Pacemakers 3" mandral intake and a 2 1/2" exhaust. It was all done on a 280 000km old bottom end. It made that power on 3 different dynos 158 on chiptorque's 162 on Mercury's and 165 @ powercruise 2008 when it was rerun on sat night the runs during the day it made 140. The dyno a power cruise is crap everyone knows that, mercury's and chiptorque's dynos are supposed to be pretty good though.

With around 18 psi boost it may want to rev. My motor has been balanced and has full forged bottom end, and a decent amount of headwork, so i guess i will have to see what happens after i get it properly tuned. As i said, revving the crap out of engines doesnt make them last too long.....

Cheers

Daz

How much rwhp/kw do you think you will get daz with 18psi ? My motor only swings around to 5300 no use reving it after that with 7psi and its got 221rwkw on tap...

phill

no idea on the figures but to the limit to rpms is determined by max g's on the pistons/crank/rods...

maximum mean piston speed of of 25 m/s seems to be a common limit chosen...so on the ford I6 this puts it at approx 7500rpm....mind u on a stock bottom end EF I wouldnt want to push it much past 6000 as this is still 20m/s....

a BA engine would be a much better basis as aftermarket forged pistons and rods are more available, then theres the head flow advantage (another topic altogether)...

Phill, my old motor had 227@14psi, to give you some idea. I am losing alot thru the transfer case and diff. Was hoping for 300rwkw, but i am now having my doubts. Surely i will get well over 250rwkw......

Absolute rev limit will be, more than likely, 6000rpm.....which is highly unlikely to see.....

Cheers

Daz

Couldn't have said it better myself.

Although I am years away from having the skills or money to go that route. Am working on the knowledge...

Remember the class I was talking about had a 40mm restriction in the intake and was still making 160RWKW... That's was the limiting factor on that particular engine - 40mm air hole, nothing more. Probably no use using 4" dump exhaust if you only have 1.5" intake!!!! Etc etc...

XR6EAT 50 - Good man. Knew someone would have seen (or know about) the real workings of these stock car things.


I wasn't really super keen on the idea of four litre motor revving to 7500 and lasting ages. Obviously, no matter what the engine is, if you take it to redline (and beyond once you've worked on it) you are decreasing its life span.

An old boss of mine (fat, lazy and DUTCH to boot) used to say that the human heart was only designed to beat so many time - So why bother using them up quicker by excersizing.

Applying that to a motor makes more sense than the human heart. At 7,000rpm you are wearing everything out twice as fast as you would at 3,500. (Okay, so complicated maths would lead you to question that exact figure, but for now - it will suffice...)

Thanks for the figures regarding 25m/sec on the piston speed side of things. It was very interesting reading an article linked from one of Tickford6's posts about detonation and shape of piston / head. Back in the day of my lateral thinking I came up with an interesting little piston and head design all by myself. Now that I know direct injection is an option, I should sell the idea to someone who isn't looking at batteries and is still in the market for burning fossil fuels very quickly.
Hmmm.

Yeahp. I hear you on the BA side of things. But that is a whole different bowl of muesli, indeed.

You know the BA head gasket I bought by accident for the EL block and head could have almost worked on the EL... Other than a couple of minor irritations (like big a*** water leaks) you could get away with using a BA head gasket to seal the combustion chambers of the E and AU sixes. Most of the oil and water would pass through from block to head and back okay as well. With a little effort drilling and welding and chopping and changing you could just about do some weird single overhead cam with a BA bottom.

au rods are longer than e series. 6.0 inch v 5.8 inch if memory serves me.

either way you go its big money. Of course they can rev that high, it is a machine, and a machine will do what its designed to do. All you have to do is alter the design to make it achieve the goal. I heard on the grapevine (so take it with a grain of salt) that during testing of the 4.0 intech they were tested to over 7k rpm, but had the limiter set to under 6k for reliability.

Obviously the cam profile lends iteself to lower rpm only.

I'm like that too. Except not dutch.

revs are only good if it is producing power and torque P=T x rpm....

first limitation is airflow into the chamber.....second is the strength of components and remember that stresses build at a geometric rate, ie your eg of 7000 rpm v 3000 rpm halving its life its more likely about 10 times the stress....

so with these long stroke engines you encounter two oposing limits...

from what ive seen the stock sohc head seems to flow to about 330-360hp, 400hp basic porting, maybe 470ish the absoute theoretical limit...the BA I would expect to flow probably 425+ straight outa the box and maybe 600 being the max limit....

you seem to be looking at the problem (the problem being how to get most power from my limited budget) the wrong way around....increasing airflow potential (via head/cam) will get you power, increasing rev potential (via raising your limiter) wont but is required after airflow mods....basic obvious advise right...

Q. whats more impressive a 4.0lt that pulls 350hp @7000 with a big cam or one that does it 6000 with a milder cam?

Q. What's more impressive... A 4.0lt that pulls 350hp or a turbo 4.0lt that pulls 350hp?


Thanks for the facts and figures GoGetta, but you are right - Stating the obvious on occasion!

I am merely gaining knowledge on the subject at hand. Am learning some useful stuff, particularly off that thread of Wagon Dad's that I pointed out earlier.

The whole premise here was not so much what *I* should do on a budget, but what *others* were doing already...

if it was a chev V8 we were talking about things would be a lot easier because what people should do and what they are doing is close to the same, they are a well known engine....

these fords aint the same, we havwent worked them out yet....the data is very hard to come by, eg head flow figures are everywhere for ford v8 heads from old windsor all the way to gt40p's but where is the 4.o I6 data.....what cams work best? what intake manifold do we run?, do we run 2.5 or 3in exhaust? what comp ratio do we run? what ign adv is best? also these engines have had till recently a very mod resistant ecu meaning programmable was necessary to get the most out of it...whos gunna spend $10G on an NA 4.0???

with all this standing in the way is it worth it persisting with it when a well developed 302 or turbo BA is available.....we are going down a path very much alone

In answer to who would spend $10,000 on a 4.0lt when there's other things available... The stock car guys who I originally mentioned love these motors... Some classes limit you to certain things --- Displacement being one of them...

as soon as I win Lotto, Ill let you know how far you can take one of these engines

Im not positive that Id throw anything over 6k on a used bottom end though. If it were rebuilt right, then for sure but ow your in big money territory, since you need a 7k rpm bottom end, 7k rpm intake, head, cam, exhaust. 7k rpm lubrication, sump, oil pump, water pump, all accesories (like PS pump which doesnt even like being spun to 5k a lot)

Its a complete redesign, and its not a case of impossible, just not good value for $$$.

Last edited by Grimketel on Wed Sep 16, 2009 7:29 pm, edited 1 time in total.