MSD ignition LEts see some

[Dr. Dyno]

some one needs to do something like this, and no matter what, I'll put money on it youll never get peak power to break 5000 rpm, and peak torque to break 4000.

That's a brave statement to make. Considering Golen's 4.6 stroker made peak HP at 4900 and peak torque at 3900, it wouldn't take much to raise those rpm peaks and you'd lose your bet.

and theres no point at revving to 8000 if peak is at 5000 and 6000 makes the same power as 4000.

Who said anything about revving to 8000rpm? The redline on most engines is set at about 10% past peak HP rpm.

 

[MudDawg]

I don't follow the idea that a distributor ignition would be problematic...and i don't follow the idea that the engine will not make power above 5k without ohc...I do agree that the hp per litre numbers cannot match a high revving pent roof, multi valve combustion chamber engine...I will tell you that my 2.5 will rev well beyond 5k...and make usable power to boot...if an engine will flow enough air (good pumping efficiency), and is thermally and mechanically efficient, the only real limiting factor is the mechanical capability of the engine to endure the rpm...

 

[tealcherokee]

That's a brave statement to make. Considering Golen's 4.6 stroker made peak HP at 4900 and peak torque at 3900, it wouldn't take much to raise those rpm peaks and you'd lose your bet.



Who said anything about revving to 8000rpm? The redline on most engines is set at about 10% past peak HP rpm.

ok, what i should have said, is youll never get peak power up that high and have ANY low end at all, so its not optimal, but yes, a motor could be built to make power that high, but it would be useless. even golens

advertised as 260hp 295lbft, assume 20% drivetrain loss- 312hp 354hp

compared to your motor, 273hp 328lbft, torque is suffering in theyre motor.

just a comparison, theyre motor makes 1.2* the hp, but only 1.1* the torque, if your motor had the 312hp, it would be laying down about 393lbft, 40lbft more than golens.

 

[Dr. Dyno]

ok, what i should have said, is youll never get peak power up that high and have ANY low end at all, so its not optimal, but yes, a motor could be built to make power that high, but it would be useless. even golens

advertised as 260hp 295lbft, assume 20% drivetrain loss- 312hp 354hp

compared to your motor, 273hp 328lbft, torque is suffering in theyre motor.

just a comparison, theyre motor makes 1.2* the hp, but only 1.1* the torque, if your motor had the 312hp, it would be laying down about 393lbft, 40lbft more than golens.

Again you're mistaken. Golen's advertised 260hp@5000rpm and 295lbft@4000rpm is at the flywheel, NOT the rear wheels. In their JP magazine stroker build-up, the Golen 4.6 stroker actually made 268hp@4900rpm and 324lbft@3900rpm on an engine dyno so it was better than their advertised simulated numbers. It had a F&B 66mm TB, 24lb injectors, and a Hooker header for the dyno test.
I agree that if you get the peak HP rpm well above 5000 that low rpm torque will suffer, and indeed that IS a limitation in the pushrod OHV non-crossflow head design of the 4.0 engine. I built my stroker with the aim of making as much torque as possible over as wide a range as possible. Given that I've had to work with technology that's over 40 years old, I think I did a pretty decent job. It pulls hard from idle to redline so the whole 750-5250rpm range is useable.
Modern DOHC engines employ variable valve timing/lift and variable length intake manifolds to produce good low rpm torque and still have good high rpm breathing. The Chevy 4.2 I6 Vortec is a good example. It makes 291hp@6000rpm (70hp/liter) and 277lbft@4800rpm (67lbft/liter), but has a long stroke (4.02") to help it make at least 90% of maximum torque at less than 2000rpm.

 

[Beej]

I built my stroker with the aim of making as much torque as possible over as wide a range as possible. Given that I've had to work with technology that's over 40 years old, I think I did a pretty decent job.

I think your 14 second quarter mile backs that up nicely...

 

[Michaelarchangelo]

Ive been following this thread for a while, and Im still trying to figure out why you would want to go through all the trouble to make the 4.0 a high revving motor? As have been stated, there are many factors that would limit such a thing. Pretty much the only stock component that would be used is the block.

 

[Dr. Dyno]

Not to mention the high cost of making the 4.0 a high revving motor.
I wanted the most bang for my buck and decided that building a 4.6L budget stroker made a lot more sense. Since it has more grunt than a herd of pigs, I don't need to rev the bejesus out of it but it's fun to occasionally wind it out to the rev limiter anyway.

 

[Michaelarchangelo]

I can understand the stroker motor, just not the high revving. If I wanted high revving motors, I would have kept my q45 or my SHO.

 

[JJacobs]

I just talk to the guys from clifford, all they do is straight 6 stuff. The stuff they know is amazing. John clifford beat a top fuel drag car in an AMC in the 1/8 mile.

cliffords engines make 450 WHEEL torque at 3000 rpm!!!

I'm calling BS on both of these statements. Proof please.

 

[Beej]

He's talking about 1/8 mile, not 1/4. Info on their page doesn't exactly back it up, but you can read between the lines. Its possible, if not probable...

 

[OT]

They were probably bracket racing and they probably broke out, so they said they beat a top fueler.

 

[JJacobs]

A TF dragster runs 270 in the eighth mile. Somehow I'm not seeing it..

 

[Beej]

It sounds like he did all his drag racing about 30 years ago and beyond, dunno if that makes a difference...
:dunno:

 

[Dr. Dyno]

I'm calling BS on both of these statements. Proof please.

It IS possible to make an easy 375hp/450lbft from a supercharged stroker, but that's at the flywheel.

 

[tealcherokee]

It IS possible to make an easy 375hp/450lbft from a supercharged stroker, but that's at the flywheel.

nope...... they do it naturally asperated.

custom intake, stand alone fuel injection system, extensive head work, custom exhaust header, and a correct cam, like no one on here uses, my self included

 

[Dr. Dyno]

You're saying Clifford got 450lbft from a naturally-aspirated I6 stroker? That's BS! The best anyone has managed to get from a naturally-aspirated stroker is 360lbft and that was Jakes Racing Engines from a displacement of 5.0L. Hesco's best dyno-verified effort was a naturally-aspirated 339lbft from 4.6L.
To get 450lbft, you definitely need some form of forced induction.

 

[MudDawg]

As far as i'm concerned, credibility at Clifford ended with the passing of Jack Clifford and the business being bought out by a former employee.

And I don't buy the idea of some double top secret camshaft...the Clifford catalog lists a cam that will make power to 7k+ rpm based on advertised lift, duration and overlap figures...the problem is the head cannot be easily "ported" to provide the VE required (and still use standard intake or exhaust)...the head would need to have radically revised port location...and that is if the valve shrouding issue can be effectively dealt with.

 

[tealcherokee]

You're saying Clifford got 450lbft from a naturally-aspirated I6 stroker? That's BS! The best anyone has managed to get from a naturally-aspirated stroker is 360lbft and that was Jakes Racing Engines from a displacement of 5.0L. Hesco's best dyno-verified effort was a naturally-aspirated 339lbft from 4.6L.
To get 450lbft, you definitely need some form of forced induction.

give them a call, the techs there will tell you everything theyre doing, he said they make these motors all the time

 

[j99xj]

Some of you will jump all over me by saying this, but the truth of the matter is that the overall horsepower is what determines acceleration and the rate at which work is performed, not torque.

Saying one engine is better than another because it makes more torque is ONLY valid when the gearing of both vehicles in question is the same.

If gearing becomes a variable then you open up a lot of different possibilites. Again, some of you will go crazy after I say this but it's true: A completely stock 4.0 with 4.88 gears will out torque a 4.6 stroker with 3.07 gears assuming the transmission and transfer case ratios are the same.

Some of you might ask "If the 4.0 makes more torque than the 4.6 stroker then why does it lose in a 1/4 mile or 0-60 race?" The answer is the difference in horsepower. The 4.6 stroker makes a lot more horsepower at all rpms.

Anyway I think 450 lb-ft out of a n/a Jeep straight 6 is not possible. I've read that you need at least 1 cubic inch for every lb-ft of engine torque you want. And unless you have a big block Chevy or Ford, you will find out rather quickly that you will need forced induction to get the torque you want.

 

[Beej]

I'm not going to jump all over you j99xj, but suffice it to say that what you stated above is an oversimplification of concepts. HP is a calculated function of torque and is calculated through this formula:
Horsepower = (torque x rpm)/5252.113

To say that torque is different due to gearing is not really accurate. You are colluding practice with theory. You are talking about perceived torque at the wheels which is not the same as actual torque at the flywheel. The 4.0 does not make "more torque than a 4.6", ever. I'm pretty sure that would be a mathematical impossibility in the same engine design.

The 4.6 makes "a lot more horsepower at all rpms", because it makes more torque at all rpms, and horsepower (which is not directly measurable), as shown above, is calculated from torque and rotational velocity, both of which are directly measurable. I'm not explaining it very well here, but others may be able to...