Variable cam timing for 348?

Anybody knowledgeable about variable cam timing? How Ferrari makes the system work? If it may be adaptable to a 348?

 

You have to be kidding?! VVT is a pretty sophisticated system on any car. You can adjust the timing of either intake, exhaust or both and do it in stages or completely variable. The actuators move the cam through the journals via electronic solenoids. The primary benefit is to optimize fuel, spark and burn based on the engine's load and rpm range. On a 4 cam engine this is pretty exotic stuff. Of course u could just do the intakes say above 4000 rpm, but still, all the parts need to be there.

Forget it dude - u have enuff on ur plate with that 355 tbs swap. You still need to optimize the fuel/air delivery and refine the ECU mapping. The last thing u need is VVT.

 

Plugzit, we just need to see how the 360 does it. Then see if any of it can be adapted to my F355 !!

Any words on this bcawright??? Since you seem to have 'access' to 360 engines ..

 

Of the systems currently in use their real purpose is to make high end HP with clean exhaust at very low rpm. None of the ones currently in use are really going to be beneficial for improving power on a motor where emmission is not a concern. Wait for electronic valve actuation. It is just around the corner.

As far as adapting goes it would be easier to just install a 360 motor in a 348 so while you are at it why not just get a 360 and enjoy all the other improvements too?

 

Plugz, have you lost it????

"Variable timing? We don't got no variable timing. We Don't Need NO STINKING VARIABLE TIMING!"

The simpler we keep these cars the better. The last thing we need is variable cam timing. Let's just focus on getting more air to the engine the simple and CHEAP way.

Group77 has the right idea. Instead of trying to suck a milkshake through a coffee straw, let's open up the path to a sports bottle size tube.

 

Now that is a good idea!!! Though it doesn't hurt to find out what it takes to do VVT .

 

Certainly I'm with you guys. My insanity knows no bounds. I'm just planning the next project after the tbs are finished. The 360 engine swap sounds good, but I've got 348 motors coming out my ears. I've gotta ask, though-How does a 430 make 500 or so horsepower? I know it's not the only answer, but I do know that back in the stone ages, we moved the cam timing 1deg. on the fuel cars and got more top end power (that's all we cared about). They used to sell offset bushings for cam timing. Everybody is using it now on any kind of a performance car. The 430 has it. Centrifugal? Electrical? Oil pressure? Howtheheck are they operating it? Is the mechanism adaptable to a 348? I need more horsepower! It's insidious! Who can tell me? If I don't find out soon, I'll hold bcawright's dog hostage!

 

One word...............TURBO!

 

Bruce, seems like this thread is going nuclear......hey now there's an idea, uranium injection...lol. Leave my dog out of this..oopps,I forgot he went with the ex...and that is your fate if you keep coming up with these kind of ideas. If it is any consolation my woman the other night had to talk me out of doing a lightweight modular tube chassis for a 355 w/hewland 6spd sequential gearbox and carbon fiber/alumin. honeycomb body panels along the lines of an F40(the one piece lift off front end fits a 355 and lift up rear can be grafted onto a GTB....I would have to fab rocker panels and doors).....there has to be an end somewhere and I agree with Vern(keep it simple).....if I wanted a 500+hp motor it sure as h*ll wouldn't be mfg'd by ferrari.....you could install a GM SeriesII 3800 V6 with TT and CART electronics pkg and it would smoke an Enzo and maybe even an FXX....the only down side is no F1 sound which I want. I totally disagree with the statement that VCT is only for top end power....it's purpose is like having 2 different cams..one for for low end power and one for top end....before when you built a super motor by using a radical cam it became almost undrivable on the street....now you can have killer bottom end to come off the line and a killer top end.....also f#*k the emissions crap in this thread, we're talking down and dirty all you can get hp here, right??
Bruce, a 348 and 355 have some potential but like any engine there is a limit, and the most obvious limiting factor is $$$$$$$$. Stay with the FI system(hilborn) we have talked about, put a 6spd in there...dial her in and you will have a one of a kind show stopper...and it ought to fly. If you desire more there is always the turbo thingy.....you will never ever never get the kind of hp from a normally aspirated engine as you can from one with a compressor.

 

Exactly!!!! Our engines have the relative position between cams and crankshaft fixed. The intake valves always open at exactly the same point in the piston stoke, no matter how fast or slow the engine is running. Fixed cam timing is only really correct at one engine rpm and one throttle setting. At every other rpm and throttle setting, the valves are opening and closing a little too early or too late. So it is a huge compromise and even more so during higher RPM's. Unless the cams are timed for that high RPM, like the 355 is.

The reason that variable valve timing works is the 'mass' of the air, can only move so fast. When the intake valve is closes, the air mass already going through the intake manifold slows down. It then has to accelerate into the combustion chamber when the intake valve opens. Variable valve timing acomodates these flow pulses to correlate with the engine's RPM and load.

So when are we getting started on this ??? Oh yeah, I still have to work on my 360 to 355 header exhaust conversion !!!

 

I agree with what you said, bc....but my insanity knows no limits. Compressors do make lots of horsepower, ok. Light weight is certainly the key to accelleration and handling (side note-I was talking to a guy who has cf done for Corvairs (!) who says his guy will make me cf bumpers for probably around $1500-maybe he's FOS-I'll discuss it with your wife ). Vern's right too.

Ok, I was talking with Dan at International Dream Cars. He mentioned the Alfa VVT system. It's a soleniod system getting signal off the tach and throttle position sensor. I haven't seen it yet, but it sounds like what I'm thinking. Put it on two cams or four. May be simple enough not to require rocket science. His eyes glazed over and he began rambling on about headwork and secondary butterflies. Anybody know that system?

Yeah, and if-when this is all done, maybe a blower or turbo, but that's been done. (Ever seen a 6-71 with 6 Strombergs on top?)

 

Heimlich effect!!!!!!!!!

 

LOL

 

If you're lucky, maybe the apple didn't fall far from the tree:

http://www.google.com/patents?vid=USPAT3641988&id=ITE7AAAAEBAJ&dq=3,641,988

Actually, keep searching. That is the first patent from Fiat. They did have a later one that used an oil pressure fed helical cam gear to advance/retard the cam timing.



Jay

 

Plugz, u got enuff 348 motors? Ok, let's get racy with one. You can explore crank replacement (stroking) along with larger pistons and valves. Throw the whole upper end on a flow bench and have them ported and polished. Let's just see how much power this biyotch can make without boost. Then let's boost this bad boy. So, what ARE you gonna do with a 700 HP 348? Maybe u better start collecting transmissions.

Remember Steve down in SD? He has a 700 HP (pump gas) twin turbo 348 he built that can drop 1000 HP on racing fuel. Full cage and racing goodies installed to run the Silver State. This car can't even pass a smog station without setting off alarms u can hear all the way to Sacramento. That's where the other engine comes in - total stock CA smog motor.

 

Sounds like alot of work and $$$ there Vince . Unless you are sponsoring ??

 

Headwork is something that'll probably have to be done. Maybe we should do research on deck heights of 360s and 430s. Maybe the crank and rods on 348 pistons will make a cheap stroker. Boost is last!

If I had Vince's money, I'd burn mine!

 

Alfa has been using a VVT system in it's 2l 4-cylinder engines waaaay before Honda did the VTEC branding and made VVT "cool". IIRC, the Alfa system was more primitive, being a mechanically actuated system with binary settings on just the intake cam. I think a late 80s model Alfa spider should have such an engine.

If you're in the SF Bay Area, you can swing by the Alfa wrecking shop, Alfa Parts Exchange, and visit my old pal Larry to have a look at the innards of such an engine.

 

Exactly what I've got in mind! Simple, mechanical. I'm not in SF area-LA-but maybe one is cheap enough I can buy one and check it out. No reason it wouldn't work on the exhaust too is there?

 

It would work on the exhaust too. I think the intake would have the biggest effect. Since the intake air is 'driven' in by atmospheric pressure whereas the exhaust is 'driven' out by the mechanical force of the ascending piston.

 

Excuse me, but aren't you wasting valuable time which could be put into something that is doable..like that 360 exhaust mod.........lol

 

No, no, no. You mean like finishing up his kitchen.

HAHAHAA

 

I hear he's doing his countertop in carbon fiber!

 

Kitchen???????????..........and I thought he was a brother

 

He might as well do it...........becuase he sure ain't doin anything to his neglected 355....lol