F4i F3 Comparison

[Mark Diffley]

Can anyone give me specific number comprisons on the F3 and F4i engine? I know that the F4i has like 11 more hp but that really doesn't matter with the restrictor. Besides it being just a newer engine, I could use some more detail on why it is better. If anyone happens to know the weight on the engine or the mounting points for bboth the engine itself and the port spacing on the intake manifold that would be great also. We are trying to make the switch from the F3's we have to the F4i, and of course we have to convince our advisors why we should shell out the extra money for an F4i when we could buy possibly 2 F3's for the same price.

Thank you

Mark Diffley
Bradley University
Society of Automotive Engineers, President
FSAE Engine/Driveline Team Member

[MikeWaggoner at UW]

10 lbs. I've never personally verified it, but that's the rumor. The F4i also has a better charging system, which is nice for the big fans and ECU's we tend to put on these cars (and then idle them....).

[Matt Ahl]

F3, F4 and F4i all have different port configurations in the head. F4i flowing the best.

[C Z]

If I remember right the F4-i has a 2mm shorter stroke. Better for higher RPM H.P. Hence the need for the head to flow better. I would think the weight would be the biggest consideration

[Charlie]

Not sure about the F3, but the F4 and F4i share the same stroke, in fact they share an identical bottom end, save for pistons BARELY different for the 2 deg valve change.

The F4i alternator will bolt right on an F4, we did that in 2002. You'll need the F4i rectifier of course.

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Mark Diffley]

Does anyone know how different the mounting points are on the F3 vs the F4/i? We have some old F3's that could be used as a backup engine, so we need to know if/how to crossfit between the two engines. Also does anyone have specific numbers on the weight?

Mark Diffley
Bradley University
Society of Automotive Engineers, President
FSAE Engine/Driveline Team Member

[Charlie]

It is roughly 10 lbs. I am almost positive that the F4/F4i differs from the F3/F2 only in the rear mounts, and it is just spacing, so you should be able to retrofit, as long as you have room in the front for that big honkin' oil cooler tank (or whatever it is)

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[C Z]

The F4/F4i run the swingarm pivot through the engine case. The F3 doesn't. It adds a couple of inches to the back of the engine so, you might need a little more length for the F4 motor.

[Charlie]

We don't run a swingarm though. http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[C Z]

exactly, I'm just saying that depending on your packaging you might have to take that into consideration

[Charlie]

Yeah I'm just saying, cut it off. http://fsae.com/groupee_common/emoticons/icon_wink.gif That's what we do anyway.

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Mark Diffley]

Does anyone know how the F4 stacks up to the F4i? weight savings one way or the other? mounting should be the same right? With that restrictor, will the better flowing head (and the additional price tag) make it better than an F4? Also, can the stock injector setup on the f4i be used with an aftermarket ecm?

Thanks

Mark Diffley
Bradley University
Society of Automotive Engineers, President
FSAE Engine/Driveline Team Member

[B Lewis @ PE Engine Management]

Hi Mark,

The stock injector setup can indeed be used on an aftermarket ECM. We use an F2 with F4I manifolds, throttle bodies and injectors as a dyno engine here at Performance Electronics. The F4I coils can also be used provided the ECM will drive coil-on-plug ignition directly like ours will.

Brian Lewis
Performance Electronics, Ltd.
www.pe-ltd.com (http://www.pe-ltd.com)
"Complete Engine Management Systems for $798"

[Charlie]

The F4i is about 3 lbs heavier I believe. That's just a guess, but it has a bigger clutch, heavier alternator with more capacity, and a slightly longer exhauts cam + cam sensor & trigger.

I don't believe the intake port configuration on the F4i is particularly beneficial with the restrictor.

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Andy Houk]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Charlie:

The F4i alternator will bolt right on an F4, we did that in 2002. You'll need the F4i rectifier of course.

<HR></BLOCKQUOTE>

Has anyone gone tried to put the F4 alternator on an F4i? Some of our team members last year thought there might be some clearence issues going the other way.

Also I think the heads will interchange as far as water passages go but the cams and head castings are different due to the integral cam trigger/sensor on the F4i head. Has anybody done a head swap between the two?

"I want to die quietly in my sleep like my grandfather, not crying and screaming like the other passengers in his car."

[Charlie]

They are totally interchangable. The alternator side cover is identical between the two. The clutch cover is different though, so be careful.

I put an F4i head on our F4 last year, it had problems in the event so we changed it, but I don't think it had anything to do with the head change. The piston reliefs are marginally different, so depending on your clearances that might be a problem, but it wasn't for us.

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Andy Houk]

I know the covers and bolt patterns are interchangeable, I was talking about the stator to rotor clearence. If I remember right one of the stators was thicker than the other. The two stators are definatly wound differently, did you see any differences in current or voltage output from the rectifier?

"I want to die quietly in my sleep like my grandfather, not crying and screaming like the other passengers in his car."

[Daves]

F4i:
Exhaust Valve Duration: 235 degrees
Stroke: 1.673" or 42.5 mm
Bore: 2.638" or 67 mm
Exhaust Valve Port Diameter: 0.866" or 22 mm

I am not certain of the duration or the port diameter, so please correct me if I'm wrong.

http://www.letu.edu/formula

My Formula Photos & Links (http://what3542.5u.com/dave/fsae/formula_photos.html)

[madhay]

Does anyone have an F3 or F4 CAD model that they would like to share? (pretty please!!!!)

[Mark Diffley]

Does anyone have wieghts on the following engines:

GSXR600
ZX6
R6

How do they stack up to the F4i? Why does Honda seem to be the most popular?

Thanks

Mark Diffley
Bradley University
Society of Automotive Engineers, President
FSAE Engine/Driveline Team Member