348 Plenum Redesign

if memory serves, you'll get an additional 1-1.5% gains @ speeds over 100mph... and thats only if the intake opening is correctly designed and positioned at a high pressure area. most of the boards theory of high flow, high velocity is inverse of what u actually want in an airbox leading up to an intake. you want to SLOW down the incoming air at the throttle plates to build pressure. but this if fchat after all....

 

Guys guys guys guys..... what's with all this harmonic flatulence stuff.

Just get some Jenvey throttle bodies, attach it to the engine, new ECU and whammo.... you got yourself 360 Stradale performance.

It's been done and it works.

 

followed by::

Sound like Ernie needs to get a clue...........

 

Sounds like you still haven't built anything.

 

Keep on with the ideas as I'm anxious to do some engine modding.

Mine would have been done by now if all my parts hadn't been destroyed.

One question. What would the effect of installing 355 throttle bodies on the 348 engine be?

 

With stock heads and cams?

I really don't think Ferrari would have left a ton of power on the table just in intake design, it would make no sense to build the heads and cams for 360-380hp and then choke it off with a poorly designed intake. It would make more sense that the heads and cams are designed for 320hp and the intake to match it. You might gain 10hp after throwing 10k at the engine in bolt ons, but is it really worth it? 10k would get you some well ported heads and reground cams to match, or even a complete 355 longblock...

The flow numbers posted earlier in the thread support that, with stock sized valves the intake has pretty much no influence on the flow, meaning it's not the restriction on a stock engine.

Good luck, but it seems to me you're starting at the ends of the engine when you should be starting at the middle and then working your way out. CARB will have no way to tell your engine isn't completely stock if you port the heads and re-grind the cams. Just keep the overlap similar to stock and you shouldn't have emissions issues. You'll also be able to bump compression if you go bigger on the cams giving you some gains across the whole rpm range. I've played with this stuff before on other engine families, you start with identifying your limitations first and then build around that. Until you identify exactly what your limitations are, you're throwing money and time away with a shotgun approach. It's the ready fire aim mentality vs. ready aim fire.

 

I've done it-it was a Stooge project. See the thread "355 throttle bodies on a 348". Really not hard other than machining an adaptor. Ran very good with stock and slightly modded ECU, but didn't dyno it. My goal was to do away with the MAFs and run velocity stacks so I was (am) going to machine one more part for a sensor pickup for the Haltec. See that thread for much more info.

 

Yes, stock heads and cams.

You'd only change the cams to keep up with 430 scuds!!

 

I started down this path last summer but life happened and I pushed it to the side. The added volume of my Euro influenced plenum pictured below didn't make power by itself. Step 2 was to sort out the rest of the intake system. I purchased the parts but haven't had the time to make it happen. The parts include a pair of 65mm tb's including Bosch tps sensors, 355 air filter boxes (I believe Bruce has the plenum boxes), aluminum mandrel bends and couplers to match. I'm on board with a Stooge intake parts pool. It gives me an excuse to wrap up what I've started.

At some point I plan to install management, the LM engine and be done with the 348 power quest.

Plus, I have the EV itch... my first time publicly admitting this problem.
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I thought I said my last word in this post but eee gaddd who welded that!!!

 

I didn't think the were ugly enough so I globbed some JB weld on the pin holes just for you. It was sliced up for testing not aesthetics and by the time its finished I hope to have included some duct tape, bailing wire, and zip ties. Thanks for the kind words though.

 

Makes me proud to be a stooge!

 

LOL

You forgot chewing gum.

 

+1

Quality Stooge welds if I must say.

 

+1

This might be the best quote I've seen in a long time

I'm in the market for a newer Fcar, but I am keeping my 348 because I love it...

 

I agree with you. I love my 348 but wouldn't mind it to be a little faster. My 430 is fast enough but I could use a little more in the 348.

 

Read the thread 348 Dyno runs.. Fabspeed has my car and is adding some great bolt on horse power mods. There will soon be some real solutions for our cars

 

Agreed , 320 hp from a n/a 3.4 , i don't think they left anything on the table. i'm sure everything is perfectly matched to make max hp. It's a Ferrari , not a freakin civic!

 

AEM makes a nice setup along with a few others. If I did not have to OBD test yearly I would go stand alone for sure with some of those pulse injectors and real spark.

348/355 would be a different animal with proper engine management.

 

My 348 has been sitting in my garage for a month now without the engine in it. Im getting some work done on the motor. New pistons, rods, cam cranks, etc.... This was the first step. How the company works is they take your engine, measure everything, flow tests, etc.... and come back with what they recommend. The full break down test was 50,000kc, 2000euro(about). I was in there yesterday and he kinda said the intake design is terrible. While this was not the first thing I wanted to do in step one he said that it would be about 12-15% it is holding back on the torque gains.

Now Im waiting on a quote to have a custom one made. I will report back when I have some more info.