355 Cylinder Head Flow Data/Max HP Potential

I dont at the moment, next time Im at the car I will
These are what they look like they are called areo boots and use lobro CV joints


https://www.pegasusautoracing.com/group.asp?GroupID=CV
https://www.pacificcustoms.com/porsche930cv-german-4.html

 

In racing, horsepower is king.

Displacement alone doesn't increase power and many times results in decreased power unless cylinder head/camshaft/flow capability is increased.

 

Huh? Exactly what I said holds true. Not increasing power with -just- increasing the displacement.

Adding a point to the compression ratio and cylinder head work is not that.

Also, stock camshafts don't mean unmodified valve events.

 

Adding a point of compression is noteworthy no?

To make peak hp at the same rpm as stock with more displacement and the same camshafts means they increased cylinder head flow and altered valve events.

If you took stone stock F355 heads and put it on a larger engine with stock compression ratio and factory spec valve timing, it would make peak hp at a lower rpm than stock.

The other thing missing, unless the info exists is baseline numbers from a stock engine.

"Toda bench test exhaust system was used"

So you would need to dyno a stock engine with that exhaust to have a direct comparison/known power gain with their engine.

 

I didn't say they were wasting their time did I?

Simply read what I said, what is there to be confused about?

"Displacement alone doesn't increase power and many times results in decreased power unless cylinder head/camshaft/flow capability is increased."


To which you respond, you don't understand because they changed things -other than displacement- and power was increased?

So lets see a dyno sheet of-

-Stock engine with Toda exhaust

-Toda shortblock/exhaust with otherwise stock components


You can't take my comment and say well they raised compression, did head work, optimized valve timing and have no stock engine baseline so that's not true.

 

Couldn't say the exact gains from increasing the compression without testing it and you likely wouldn't do so without changing valve events.

What are modified valve events? Valve events are when the valves open and close, so by modifying them I mean altering them from original.

Once again, the "56" hp gain is an assumption by you as there is no baseline dyno from Toda with a stock engine and their exhaust system.

 

Once again, the power doesn't come from the compression ratio (or displacement!) alone. You seem to be glossing over this while repeating things that do nothing but back up my statement.

Your "56hp gain" is your assumption vs as you say "standard 380hp"

Certainly a complete custom exhaust from headers to tips along with engine management tuning and camshaft optimization is worth power over the original F355 computer/valve timing, headers, exhaust and 4 catalysts?


So what are Toda dyno results for a stock F355 engine with the same exhaust system/engine management used on their UME spec result?


I'm interested in this of course but don't want others to think things like "Horsepower sells cars, Torque wins races" is true.

 

LMAO, I do EFI calibration for a living, for over 20 years now and involved with various forms of racing for just as long as well.

Just finished building an engine for one of my own cars a few short months ago. And converting it to EFI, flex fuel, and of course tuning it.

Really I don't know why you started the thread. You ask questions and refute any answers, just wanting people to agree with you.

 

It's all so assinane. Stroker for what? Change pistons and put 2 little twin scroll turbos on it for god's sake. leave the heads bone stock no less.

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And I was having fun reading internet & back yard engineering at its best, ohh well back to rocket science and new quantum physic laws, this party's over

 

For now, the stroker build ended up exactly as many suspected. Fizzle. But who knows what the future holds. I'm holding out for it!

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Thanks INTMD8

 

^ LMAO

 

About 15 years ago I used a CFD simulator to investigate a subset of your question.

That is:: How much HP and TQ could one get out of the F355 engine without going inside--but headers, exhaust, intake system are free game.
The simulator used perfect ignition timing (I had no control over this)

Under street realistic situations I got to 440 HP.

To get there, you need::
a) different velocity stacks (2%)
b) different Helmholtz resonator (5%)
c) custom headers with an expansion from 38mm at the head to 42mm (50mm long) down pipes to 50mm pipes after the 4-2 portion and 60mm pipes after the 2-1 portion. (2%)
d) an expansion chamber after the headers (roughly 16 inches long 3" in diameter) (1%)
e) and a special trick--The velocity stacks terminate inside a jar (just lightly bigger than a quart) which is then fitted inside the Helmholts resonator and has an exotic shape of its mouth (worth 20 HP all by itself) (5%)

All without going inside the motor. Stock cams, stock compression, stock valve timing, stock RedLine,.....

I tried porting the exhaust as the early simulations showed insufficient flow, but once the headers tube diameters increases and were coupled with an expanding pipe, this problem went away.

Oh, and BTW: when fitted with my models of the velocity stacks, Ferrari Helmholtz resonator, and Ferrari headers, and air cleaners I got 378 HP and a TQ curve that looked identical with the published TQ curve.

This is only simulation

 

My experience on two engines
One was a 355 very similar percentages
My 355 gained about 25 hp from air box, headers and exhaust others results were similar
Other engine was similar about 7%
Other engine also got about 5% from cams and compression to 13.5 not stroked
Cam timing had about 1.5 degrees more overlap from each.
I am guessing but I would think very similar results would follow with our 355 based on correlation
The result was the torque band gained about 10% from about 1000 rpm less and stayed very flat and only lost torque within 725rpm of factory redline

based on that I would think real world gains of 40 to 50hp or 10 to 12% are quite achievable.
My guess is this is why others choose to lighten car by 10% and get on Jenny craig
Cheaper and easier.
Now doing both would be very good imo

 

56hp gain on an engine that produces 109hp per litre is incredible, more so being naturally aspirated. Like ive said, if you want a faster Ferrari, buy one. Otherwise no matter what you do, don't race a new Yaris.

 

The ups and downs of a highly modified F355 engine.

Easily breaks traction @17s
Engine explodes @48s

 

3.5 litres should make 350hp on a good day. The fact it makes more is a real feat, especially since they guarantee this from the factory and give warranty. That's it folks, 375 give or take.