355 Cylinder Head Flow Data/Max HP Potential

Does anyone have any idea of the max HP potential of the unported OEM F355 heads ?
Would they be good for say 450-500 HP out of the box in a NA application?
I know the early casting heads had better flow potential, albiet with weaker walls, but by how much did they outflow the latter style heads..?
Are gains to be made by porting/oversize valves/48mm Throttle bodies.

Im having trouble finding a Ferrari specific cylinder head porting specialist.. all I seem to turn up with is generic head specialists..any ideas of from the gurus out there..?

 

Many thanks for the reply INTMD8

I'm just curious to know just what the latter F129C OEM virgin F355 heads are capable of flowing right out of the box .

The problem is a paucity of flow data online regarding the F355 heads, and AFAIK no one has 'modelled' the F355 head to do a virtual flow analysis, and make changes in the programme to give any accurate figures..AFAIK, no one has a CNC programme for the F355 cylinder head, nor do templates exist, and if they do they are probably kept under wraps.. and rightly so.

Obviously you can go too far and get the 'cfm' numbers right whilst destroying the low down air speed entirely and making the car a pig to drive.

This is compounded by the fact that very few Ferrari specific cylinder head gurus exist out there, and if you do.. are they experienced with the F355 head?

Im sure the F355 cylinder head gurus exist but where are they? and in the absence of this punters like me usually take the safe way out and get a reputable generic cylinder head specialist to do just a polish and light tickle.. maybe some short side radius work

If the F355 head is capable of flowing 450+HP out of the box.. you realy don't need to take the risk of porting it then do you?

Can anyone point me in the right direction for this sort of stuff?

Steve

 

Ferrarium, I agree with that statement.. if we were talking about a 3.5L Ferrari engine.. However the advent of the F355 stroker has changed all that..
500HP is achievable nowadays..

https://www.toda-racing.co.jp/en/product/piston/f129b-strokerkit.html

 

Thanks for joining the discussion Targatime, im grateful for everyones input on this.

The bottom line is I don't know how much is left on the table..?! Im simply looking for the few people that may know...

As you say, out of the box the F355 made a record breaking 108.7 hp per liter, up from 348's 88.1 hp/litr.
Thats assuming that Ferrari were completely honest about the matter, and the only way to realy know this is to drag race/dyno your car.

That was with 3496cc 'back in the day' mid 90's
However advances in fuel, electronics, injectors etc and the advent of the stroker 355 however now introduces a new level of thinking,
Lets take the TODA MATSU spec engine as an example.

Displacement 3859cc (C/R 13.3:1) TODA (Solid) Matsu camshafts 295/10.2 IN & EX 492ps/8500rpm
Requires minimum 100 RON and if TODA HP figures are to be believed.. 491HP from a 3859cc yields 126hp/litre

That does not mean if you purchase the TODA MATSU engine and stick it in your car that you will get the same HP figure.
That figure was with dervied at TODA with ITB's,no air filters, race fuel and staright pipes and 4:1 GT300 headers.(45mm primaries)
Our cars have airboxes, 4:2:1 headers, bypass valves etc..

The best example of this on this forum be found here..(see post #60) (8.3% HP deviation from TODA dyno figures)
https://www.ferrarichat.com/forum/threads/toda-take-spec-355-rebuild.628631/page-3

Kudos & big thanks to the owner for sharing.. id love to know exactly what TODA did to his heads? Port job or just light tickle and polish?

So if you were going to go balls out and pull the trigger on a TODA MATSU engine, or even build your own stroker engine, these things have to be factored in.
But I would say 450-460 HP in the car is achieveable.

But getting back to my original question..

Does anyone have any idea of the max HP potential of the unported OEM F355 heads (early or late casting)?
Does anyone have any flow data to suggest what is achieveable without scarificing air velocity down low.
Does anybody know any F355 specific head porting specialists?

Steve

 

Does anyone have any rough idea what the nominal flow nate is for the latter 355 heads out of the box?
Surely someone must have flow benched a set at some time on this forum?

 

Yeah I have read that.. Is he part of the Cabal..? Big Kahoonas to put in oversized valves. Does anyone have experience with Sabre heads in the UK.I have emailed him but as yet no dice.. CFM picked up but without velocity figures not sure what the changes mean ..Good pickup SoCal

 

A summary of the results

FERRARI 355 V8 5valve. Inlet- 26.5mm valves(OEM)
26.33 52.1 76.17 97.94 114.77 121.92 127.45 130.91 133.68 135.75 137.13

As above, reworked and fitted with larger valves- restricted by use of existing insert- also considerable combustion chamber reworking was required on one head due to a large volume difference to it's other casting, some 2cc of volume.

28.56 56.64 83.16 106.67 121.52 130.55 136.1 138.56 140.39 142.23

FERRARI 355 V8 5valve. Exhaust- 28.45mm valves(OEM)
16.78 34.64 53.32 68.35 76.73 82.7 88.1 90.7 93.11 93.65 96.85

As above, reworked and fitted with larger valves, this to reintroduce desirable features removed by the factory? poor porting, the inserts were left unchanged/unaltered but the ports reworked. New valve size 30mm. An excellant result.

21.55 45.43 67.14 83.95 96.84 103.7 109.37 112.9 114.76 116.89

 

Still the comments about the F355 head being outsourced for factory porting doesn't inspire confidence....especially when different operators work on the same F355 head resulting in inconsistent ports??!!? More of a reason to flow check the heads!!

 

What I am trying to achieve is to maintain the factory engine bay look & F1 sound of the f355, but just with a little more grunt.
Max Hp is not the goal here.. Its driving experience and pleasure..If that translates to only 420-430 HP at the crank.. so be it!
But I think you can get a little bit more..

The facts are that the 2.7 355's make 30-40bhp more than the 5.2 for reasons well known to forum members.
As I have a 5.2 car I have decided to approach this problem with baby steps

Phase 1: Covert to 2.7 (30-40hp gain) This is easily done with an aftermarket ECU, 2.7 airboxes, 2.7 exhaust.

So now youre a 2.7 car.. but wait, there are added benefits. Now you can..

Run MAP based tune. (and believe me it runs far better!)
Run test pipes and CAT delete(no more SLD/CEL)
Run better injectors with finer spray pattern,
Now you don't have thermocouples fouling your exhaust.No more MAF sensors fouling the intake
And more importantly switch maps easily to run higher octane fuel ie E85 and flex fuel, even N20!
Air injection pump delete, immobiliser delete, evap canister delete etc..

And if you are happy with the result.. you can stay here in Phase 1 happy land. If not please refer to phase 2

Phase 2

This now sets the platform for forced induction or higher compression NA builds.

I agree with INTMD8 that you can go backwards building a NA stroker engine..but if you approach the issue carefully, with basic first principles and not go overboard..I think a happy medium can be found. The fact that TODA has done it means its achieveable.. and by default they have given you the recipe.

Now you just gotta 'roll your own'

Of course at any of these stages..(Phase 1 or 2) you can default to what can only be described as a very sensible conclusion from INTMD8

" it was far more effective to reduce weight of this car than to spend loads of money to increase an already impressive specific output."

We buy the F355 because its a feel good car.. The sound, the 9krpm, It truly is an experience.
Like everyone else on this forum.. Im just looking to make that experince a little bit better

 

BTW.. I just spoke to a cylinder head expert. he is under the impression that as the port to valve are ratio is so high in the F355 head, that it would benefit more by oversized valves in the OEM ports compared to OEM valves in bigger ports. On the exhaust side its easy.. On the intake side a little harder. But as we have seen in an earlier post.. it can be done..Also oversized valves helps them ceate a better radius on the back of the velve thereby improving airflow more than with the OEM valve?

Also he said that it may benefit from larger throttle bodies..
45mm TB's = 45bhp x8 = 360bhp
50mm TB's = 50bhp. x8 = 400bhp

Has anyone ever heard of anyone that has ported the OEM Throttle bodies with any gain.. and at what power levels you would consider it?

 

On that point.. I must confess... ZERO experience, but I know the guys that do..

 

Mark, Thanks for the heads up.. Cams are close to the TODA Matsu Spec.

MATSU Solid camshafts, Solid lifters: 295/10.2 IN & EX (NB: std cam of IN 270/8.9 and EX 282/9.2 (HLA)

I have just been informed that oversize valves are available too..

 

Does anyone know of a source for aftermarket connecting rods for a F355?

Im curious because in the TODA Stroker kit they re-use the original Titanium F355 rods..
Is this because they could't source aftermarket ones when the kit was developed almost 15y ago?

Im looking for some dimensions on the F355 OEM Titanium Rod.. I know they weigh about 401g.. with the con rod bolts.. but I cant find any information regarding the rod length... ??! Does anyone know what the rod ratio ( Rod Length/Crank Stroke) is in our engines?