As the topic. It's based upon a 93:ish 4.0 bottom end and the rest of the bits are from a 2.9i 24v BOB cosworth. Just missing a few bits to be able to put it all togehter. But here are a few old pics from how a few bits fit together.
The rod modification:
Bush in small end increased to 24.0xmm
Big end reised to ford bearing size
New locking grooves where made for ford bearing
The big end with was narrowed and also a chamfer was added.
Did aslo make a oilspray hole just like ford rods got....
If I am happy with the car? Nope, it is lots quicker than a stock 2.9 24v, I out run my brothers scorpio cosworth with ease, if I pull from 1500rpm in 5th gear he can be at whatever revs he likes and he cannot keep up...
After 4000rpm the engine looses power, I've tested a few different setups, actually I was going to test another one last night but due to a fuel leak I had to cancel. But I think the main reason for lack of power is due the inlet manifold. Still the engine doesn't pull bad after 4000rpm, but I think it could pull better....
On the 4.1 engine a piston pin snapped, so I replaced the bottom end with a stock 4.0 one. But now the 4.1 bottom end have been repaired, uppgraded with a girdle, I hope to have it ready to spring. Then engine will have custom made inlet cams, a slider throttle with short runners etc...
I will make a movie soon, so you need to wait until then to see how it performes...
Cossie, I don't think the techs will tell that you got a 4.0 instead of a 2.9....
Welcome. The 2.9 heads are not really much larger than the SOHC 4.0 heads. The rpm limits of the DOHC heads would be more than the SOHC heads, but if they don't flow much more than the SOHC heads, the gains would be limited.Hey guys, greeting from Russia. i have read this post and have some questions. I ride on Mustang v6 4.0 sohc 2005 MY. My serviceman told me that i can use 4.0 block with 2.9 Cosworth heads and it gives me over 400 hp.
Can u help me with information of setup ? also if i buy supercharger or turbo, what boost will be able ? also if there are any forged rods or pistons or how can i make it stronger to boost ?
Thanks !
Thank you.Welcome. The 2.9 heads are not really much larger than the SOHC 4.0 heads. The rpm limits of the DOHC heads would be more than the SOHC heads, but if they don't flow much more than the SOHC heads, the gains would be limited.
There was one person who finished his 4.0 DOHC engine, but he didn't reply again after the initial start up. I think he didn't have good tuning to sort it out.
To make the DOHC head swap viable, they need to have more flow capacity than the SOHC heads. If I was doing it, I would begin by learning the flow of both heads, ask some engine builders what flow improvement would be worth the trouble for the swap.
That's very interesting. But i m afraid that my engine will be killed as soon as possible on 18 psi.Try this thread by a great member who has a supercharged 98 Explorer, 4.0 SOHC, 5R55E. It runs about 13 seconds, boost is up near 18psi. His engine is stock I believe, but there are some aftermarket pistons and rods I think. The engine is very capable, the 5R55E automatic is a little weak to push those power levels though.
My 98 super charged EX
The whole set of DOHC parts etc, are interesting for sure. But the bigger discussion should be the actual head flow of the DOHC heads, and the capacity of the 5R55E.
Several people have done well with the trans, that may be a hit or miss issue to have those survive at higher power levels. I would concentrate on the transmission in every way, cooling, VB upgrades, the PCM tune(after VB work), every possible modification is what I'd do there. I would not rely on luck to have the 5R55E survive at those power levels.
The DOHC heads on a 4.0 have not been documented in any useful way. Actual power numbers are needed, a full power graph, plus head flow figures. If the heads don't flow any decent amount more than the SOHC heads, than the whole big DOHC project is not worth the trouble. Given the age of these now, I wouldn't rely on finding results data from others.
I would locate the DOHC heads and have them flow tested, even if that could be done in Europe(before shipping if you found them there). I don't know what the SOHC heads flow either, there is not much useful data about the results(details besides power) of that engine either.
In a SBF head, flow should be way over 200cfm for performance, stock GT40's hit around 190cfm, those are low performance heads. Most older aftermarket heads could hit or be ported to the 250cfm range, high used to be 270cfm. Now prices have gone up, but the flow has too, 270 is somewhat common($1500 heads), but 300cfm is more common too($1800+). Top end stuff is easily 320cfm and up to over 400cfm($4k stuff). The TFS heads I found to build my boosted SBF flow about 315cfm.
You should hope the SOHC and DOHC heads flow 200cfm at least, and potential be there for 230cfm or more. I have no clue about those, just a random guess seeing the port sizes. Airflow is power, the boost adds more to that. If you can increase port flow by 30%, the power should go up some similar amount. So adding 30% more boost won't add 30% more power, restriction and heat(IAT's) cost a lot of that.
But actual airflow of the critical parts(heads, intake, exhaust), should achieve much closer increases to the flow gains, versus boost gains. Mainly in very restrictive combinations, like the stock 302 Explorer exhaust issues, and the stock heads. The V6's have much better exhaust manifolds than the 302, plus the slightly smaller engine(4.0 versus 5.0, 20% less).