How about 550 throttle body on 348 project?

If I'm reading UK english right, it has ported heads and intake, high lift cam, high flow injectors, tubi with no cat. did I read that right?

those appear to be crank numbers is that correct?

I can't open that dyno either dyno graph since I'm not a memeber of that forum, can you paste them in here?

 

I think so - Justin is a member here - I'm sure he will clarify what he has had done - the chart is attached in post 99.

This is an interesting thread - It shows John Stechers 348 - also another chart from Justins car.
http://70.85.40.84/~ferrari/discus/messages/256120/206770.html

What looks strange to me is the amount of power that Justins car is producing at only 5500 rpm - 395bhp?

 

thanks.

The rpm looks right to me and pretty much exactly what I'd expect. On my QV heads, it was simply not possible to get the flow above 112 cfm @10"h2o and the 348 is the same casting. That will feed a 3.0 liter to about 7400 rmp or a 3.4 to about to 6500. I needed to have custom intake valves made to get the flow that high, if he's running stock valves, the 6200-6300 peak seems right. If He could have gotten the flow up to 140-150 where that engine wants it to be he would have made another 100hp I think.

 

Would it make sense to simply polish the ports? Or, is valve size the only limiting factor on flow? Back in the old days working with iron castings which were a lot rougher, it did some good, but you gave up a little low end. I realize the castings are much finer now. Another way to ask-is there anything a cheap shadetree can do to increase port flow? Let's assume the heads are off anyway.

 

Well one thing I have seen people do is shorten the intrusion of the valve guide into the port a wee bit. They may not last as long depending on the amount shortened.

 

Mark - that would be nearly 150bhp / litre? (500bhp)

That would be mighty impressive but I just cant see how that would be possible with the standard plenum & Tb's - IIRC its running a standard ECU with Dimex? powerchips - it looks like the standard plenum & tb'b flow enough for 400bhp as well?

 

Am I right in saying that anything around 120bhp/ltr (N/A) is pretty impressive? (N/A and on pump gas)

 

yes - very impressive indeed.

But again, it's deceiving. Yes, it may make 120 hp/liter, but make it at 9000 rpm with nothing below 5K.

It's similar to what I realized when I was doing multiple dyno runs on my car - you get a bit addicted to chasing peak numbers and loose applicability to the real world. I learned that while important in tuning and quantifying what you no-**** actually have, max dyno hp/torque is but one indicator and tool to tune the entire engine. As many have said - the shape of the curve is more important to tweak the engine to how you want the CAR to perform.

 

I know people do that, but it's never seemed like a good idea to me. It causes the guide, valve and valve seat all to wear at a much higher rate.

 

The simple answer is no, it's WAY easier to make the heads worse than it is to make them better. I bought a scrap head for practice....and sent it to a buddy of mine who does nothing but port heads for a living. Their is a lot to be said for talent.

I haven't had a 348 head on the flow bench, the QV head is the same casting, but from what I can see, ferrari did a better job porting the 348 version at the factory. The QV is restricted at the manifold flange, but on the 348, ferrari opened that area up quite a bit.

The next area is around the guide. One answer is to cut off the guid, but the right answer is to widen the port a bit at the guide.

The next spot is the radius on the bottom of the port and blending into the seat could be a lot better.

The next place is the seat itself, a radius cut seat works much better than a 3 angle seat.

After all that is done, the valve needs to get a bigger.

Then a cam with more lift, .400" or more is really what the head wants.

Then, on a QV, the next step is to throw away the intake manifold because it will never ever flow what the head is capable of. The 348 intake looks much better, and certainly your 355 set-up is fine.

 

Yes they would wear quicker . It seems that f-car guides are short enough, from the pics I have seen on this forum.

Though may work for the guy that puts about 500 miles a year on his f-car and is not planning to sell it.

 

You're right. 150hp/liter is possible, but high for a street engine. 130 is more realistic for pump gas.

The 348 intake looks pretty good, but I've never had one on a flow bench. If the engine is making 400 with the stock parts, then yes it flows enough.

One note of caution is that different dynos read different number. The gold standard these days for comparing across dynos is dynojet, you can go anywhere in the world and be withing 1%-2% of anywhere else. T

he other think is this was a rear wheel dyno run, but crank numbers are quoted....but we don't know what they used for driveline losses. I've seen dyno operators use numbers as high as 30% and as low as 15%. For a 348 I think 15%-16% is probably right, on a QV it's more like 17%-18% due to the drop gears.

The bottom line is that without a basline run or at least another stock car on the same dyno, it's hard to know for sure what exactly the numbers mean. I'm sure it'sa great result....I'm just not certain exactly how to compare it to other known results. The most telling is that is seems to beat a 355 to 110, that makes me think 400 is a good number, but it could be +/-20 I guess.

 

I saw you cautioned about wear too, I just wanted to reinforce that a bit. IMO, shortening the guides is a last resort and is not required on these heads. In fact, I've never seen a head that required the guides to be shortened to make them flow properly, that doesn’t mean there aren’t some out there, but a QV/348 head is not one of them. The QV/348 head actually flows really well and after porting has the highest port velocities of any head my bubby has ever had on the flow bench.

It's a good design, but but seems to be all done at about 112 (@10" h2o) for some reason, at least on a 308 cylinder, it might do better on the larger 348 cylinder.

 

I was looking at your profile pic, niiiiiiice (insert borat)!!!! How much boost are you running??

 

Thanks. That system was at 22psi (at redline) and 420rwhp.

I've since removed it and sold it to another fchatter and I'm building an even better one. I'm thinking it will still be in the 20-22 psi range, but with the ported heads and new cams I also needed a higher flowing intake and a bigger supercharger. I'm thinking it's going to be in the 550-600rwhp range.....but a it appears my out-of-control pool/patio project and the pending birth of my first child will prevent me from fnishing it for this season

 

I know where you are coming from, I too am saddled with a "money pit" of a house among other things . I can't even get my capristo and aluminum hat brake rotors for another few months . Though I wish you all the best and congratulations on your 'pending' family addition .

 

Don't tell me you STILL haven't finished the kitchen?!

 

Nope, still need the task lighting, range hood and knobs/pulls for all my new cabinets. Should take me another few months to that alone

 

This thread has been seriously deflected.

 

I'm not so sure about that...any project of this magnitude has side issues that must be addressed prior to completion. Those of us with wives, other cars, kids, jobs, etc. know that for sure!
"You're not gonna spend another day on that car til you finish that kitchen".....sound familiar?

 

OKay so let's get back on topic.


HEY DAVE!!!

Did you get that thing on the rollers yet????? I'm very curious to know how much power you turned loose.

 

LOL very familiar indeed !!!

 

+1 and what kind of exhaust are you running???

 

His made a custom x-pipe set-up.

 

Set up for first week in April. Runs and sounds awesome. Sounds like two GSXR's with Yoshi slip-ons, but not too loud. I need to make a digital video, anyone close by to shoot some short clips. I won't drive it until the winter salt is washed of the roads. Wisconsin loves to dump this s#!t on the roads.

Its a second generation of my first straight pipe x-pipe exhaust. similar setup just with a perforated x section wrapped into a muffler, with ceramic sound blankets.

Left to do; wire up fog lights, turn signals, check spring rates, set-up ride height, my aligment specs, check bumpsteer, camber gain, toe, scale it, etc, all that junk...
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