4.6 modular v. 302/331/347

[Cliff Beer]

I'm looking into increasing the power in my CAV - currently with a Ford Racing 302 and Holley. A stroker 347 with webers is certainly tempting (have been watching the T&L review thread) but I'm also intrigued by the possibility of a 4.6 modular with webers as sold by KarKraft. See here: 4.6 WEBER and here: YouTube - Kar Kraft Weber Modular Engine

My main points of inquiry are:

1. Dimensionally, even with the twin cam heads I'm guessing that size isn't a problem but perhaps it is?
2. Trans adapter - anybody know of an adapter kit for an audi 016 for this engine?
3. Weight - the ally block on the modular likely saves some weight over an iron block 302/331/347 however I'm not sure if the modular twin cam heads add an equivalent amount of weight back into the total package. Anybody know about relative weight?

I'm intrigued by the 4.6 modular because I like 4 cam engines and I'd like to save some weight if possible. The KarKraft spec for the weber induction is 400hp/360 torque which is plenty for me. The KarKraft complete price of $8,900 certainly is tempting.

Thanks in advance for any thoughts.

[Ron Earp]

1. Size is a problem. You'll spend a lot of money to get that to fit as well as redesign many components.

2. Not sure on that one. I think there is one for a 01E but that is a different animal than the 016. I am sure someone knows better.

3. The mod motor is heavier than a iron block aluminum headed SB Ford, which is what you have isn't it? I can't imagine anyone putting iron heads on your motor, if they did they should be strung up, it is 2008 and ally heads are cheap.

You could make more power, with a lighter weight (especially if you spring for an ally block), in a smaller package, and for less money with a SB Ford when compared to a modular modular motored car.

[chuck smith]

Cliff, I feel the width of the motor(wider than a 460) will be prohibitive and finding headers will be a big and expensive challenge. I would be inclined to think that a really high end set of heads(maybe Craft stage 111's), bigger cam and better induction set up (webers?) will yield excellent results for the least bucks and have you back on the road the quickest. The weight savings over a 302 will be modest if at all.

[Fran Hall RCR]

Cliff,

we installed a 4.6...its a big lump..we made it fit but the custom fab for all the support items..headers/AC etc etc will be a fairly sizable undertaking...

[Ron Earp]

Do what Chuck says, get some new parts. Even with a 302"displacement you could get 400hp/360 ft-lbs with bolt on heads, cam, intake, and carbs. Some AFR heads milled for good compression, proper pistons (might can skip this step depending on what you have), bigger bump stick, single plane intake, a nice 4bbl, and most importantly, some tuning and you'd be there. Or do it with Webers, either way.

If you've not spent some time on the dyno with your engine the way it is you might be leaving a lot of power on the table as it sits. Might want to look at that before doing anything at all.

[WesS]

cliff,
re: fran's post: the big lump was in my rcr40. we ended up taking it out because of all the fit and size problems. way too big. put a 4.0L lexus in it. smaller, more powerful, more efficient, duel ovhd cams, etc. everything the mod engine has, only better. sorry, no pictures. oops, maybe i do. will look for them.
wes

[Cliff Beer]

Thank you gents, very helpful information and pictures. As usual, somebody here has already given it a whirl and done the heavy lifting. Hhhhmmm, re-thinking that 4.6 modular idea now.....

Doesn't sound like the right engine choice at all both in terms of size/packaging and weight (along with other complications you have helped me appreciate more fully!).

That 347 with webers is looking a lot more appealing now. I'll do some research on the alloy block option.

Again, thank you!

[Keith Hardy]

The 4.6 also appears to sit a lot higher than SB unless it's an optical illusion. That wouldn't be so good for handling either.....

[Bill Hara]

RF did (and I suppose they still do) a 4.6 modular. They now (along with DRB) do 5.4 mod engine fitting too. Here are a couple of shots of a 4.6 in an RF

[Andrew E]

Hi Cliff,

I own a 302 with an 01E with LSD 8 barrell\cross over. I've just finished buildimg an RF for a mate with 4.6 01E with LSD eight barrell|cross over exhaust.

Compaing the two cars is interesting, the 4.6 certainly is a much heavier car but the engine is very smooth and loves to rev to 7000rpm. It does lack the low down torque of the 302 which I limit max revs to 6000. On the road it would be a tough choice to pick between the two cars, we will both be doing some track together later in the year so then the fun will start for real comparisons The 302 would have more options for tunning such as stroker cranks.heads and camshafts and other aftermarket goodies.

The chasis is considerably widened to fit the 4.6 engine and the heads look massive vs the 302 setup. The rear clip of the 4.6 is heavily cut out to enable clearance for the heads and much wider valley of the engine. Ford GT heads and cams are a tuning option for the 4.6 though there is not much room height wise to consider supercharging.(then you really start to get away from the gt40 look)

If your car is already a small block I would be moving towards a stroker motor with good heads, conversion to 4.6 after the event would be a moutain too hard to climb.

(I had some photos looking across the two engine bays, but I can't find them will post when I do)

Andrew

[Cliff Beer]

Hi Bill and Andrew,

Thank you for your thoughts, and pics - very helpful and informative.

Not having studied a 4.6 mod in person I had no idea as to the relative sizing - obviously, you and Ron and Fran have enlightened me on this point, and the related install difficulties, so the stroker route (as you suggest) looks like a much better path. I'm pretty handy in the garage - have done engine rebuilding and some fabbing and also have a full shop inc. lathe, mill, brake, press, etc. but not much time, so, some easy mods on the basic SBF config is more practical.

Very interesting to read your comparative impressions of the two cars on the road - yes, will definitely be interesting to see the contrasts on the track! Congrats on completing the builds - must have been a lot of work!

Cheers.

[Bob Putnam]

I've found that the biggest problem is fitting the exhaust within the chassis pontoons. The lines perpendicular to the flange faces here show the centerline of the ports.

[Ron Earp]

That is a really good reference picture Bob, thanks for posting that one. I'll keep that in memory for future reference.

Cliff, bear in mind your 302 is a bit smaller than the 351 Bob shows due to the deck height of the 351 being higher and the heads being pushed out a tiny bit more.That modular really is huge.

What FMS motor did you have? That would give us some indication of the cam and other parts. It really could be as simple as a cam swap, carb tweaking, and you could obtain a significant hp increase. Do you have any idea what sort of rear wheel hp numbers you are putting down now and if it is 100% optimized?

[Jim c]

The info I have is that the modular is 110pounds heavier than 302.

I have fitted a modular to my RF and it is tight and compromising.


Jim

[Cliff Beer]

Hi Ron,

Thank you. The engine choice and install was done prior to my owning the car but I do at least know that the engine is the following engine: Ford Racing Performance Parts [M-6007-XEFM*] The carb is a Holley double pumper but i'm not sure what CFM spec. Ignition is basic Mallory.

In light of the size issues with the 4.6, I'm now trying to figure out what low hanging fruit there may be to get a little more hp. I'm considering webers from here: eBay Motors: Weber 4 X 48 IDA Carburetor Conversion for 302 FORD (item 150197779934 end time Dec-31-07 05:14:36 PST) Seems like a pretty smokin' deal although my understanding is that the webers might only gain 20-30hp (love the looks however). I'm guessing there are some better heads than the FRP heads, and, a 347 stroker kit would go a long way as well, particularly with low-down torque.

Any help/guidance you can give is much appreciated - I'm a rookie with regard to SBF tuning but eager to learn.

Thanks.

I haven't had it on the dyno (yet).

[Fran Hall RCR]

Call Keith Craft...he has done some great engines for RCR customers...he can accomodate anything you want.
Also T and L...regarless of their minor Faux par recently,Lloyd is a stand up guy and they will build you a flyer of a motor...they built some of the fastest Busch race motors going ....

I would stay clear of Roush and Ford Perf. Prod. personally....

[Howard Jones]

Ron' s favorite picture.

[Ron Earp]

Howard, that is a favorite picture for sure!! Damn mod motors are too large!!

Cliff, I'm not being a stick in the mud - but have you dynoed your combination and have you spent time tuning the motor on a dyno. Seriously, you could be leaving 50 rear wheel hp on the table with ignition and fueling, maybe more.

That motor you have has the X grind cam and should be a fairly strong engine. Now it could very well be that it is tuned to the max and delivering around 300 hp to the wheels on a dynojet and you are not happy with it, but without some dyno numbers it is hard to say.

Hate to see you spend money chasing a new motor when it could very well be carb tuning, ignition timing, or even a cam/head swap could put you where you want to be.