Why don't I hear more about C30 and C32 motors with high performance cams?

Speedmaster

Speedmaster

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So, as I try to better understand options for getting more HP out of my C30a, I keep going back to wondering why we simply don't put in "hotter" cams, and proportionately increasing capacity on the intake and exhaust.

Then, it occurred to me, this is not a Fiat. And, I am not still driving my X 1/9 with a larger Weber carb and a hotter than stock cam.

So, I am curious. Why don't we do just that? Don't cams afford longer valve position times (more flow in/out)? Wouldn't adding a higher-flowing intake and exhaust allow for those longer "open" times to add more HP?

I am no engine builder so I am sure I am missing something basic here.
 
Well you don't have to be snarky about it.

Yes, I know what VTEC is and like I said, a hotter (set of VTEC) cams...do they exist?
 
yes comptech which are not produced any more, and toda which are.From comptech's literature the cams where good for 25 hp with supporting E/H/I mods.
 
From what I understand the performance gains are minimal as Doc mentioned. Honda left little on the table for improvement. The high cost of cams and installation don't add up to the hp figures. I'm sure a high lift cam sounds marvelous though so maybe it is worth the cash?
 
The cams are for the NA purist....going all the way to a stroker with ITB...those cars exist and can be street driven with about 380hp...
 
i dunno exactly why there isnt a large selection of aftermarket cams either, but then again there really isnt a large selection of much anything NSX-related. probably too small of a market to have enough buyers of something with extremely expensive R&D.

as for it being VTEC and thats why it doesnt have/need cams isnt really true. B16/18C engines have plenty of selection of cams to choose from that offer much more aggressive cam profiles while still using the VTEC system. Even D16 single cam vtec engines have a selection of race cams to pick from. but the cars that have these engines are wayyyyyy more popular in numbers to definitely justify the engineering to create aftermarket cams.
 
What would you like to know, I have a 3.2 with the SOS cams which are not much different to the Comptech cams. I blew the head gasket on this engine at the track so that's being rebuilt now and going into something else with hotter cams again and a ITB setup so stay tuned on that one.
So in the meantime we built my original 3.0 into a 3.1 with a TODA piston kit and have the ported heads to 3.2 spec with SOS valve kit and the SOS cams going on this block its fully balanced and all new bearings etc etc,etc.
The 3.2 with a stock block and ported heads and intake/TB with those cams and a link ecu ran at 301hp and was significantly quicker than a stock 3.0 with normal bolt-ons.
The 3.1 is going back in the car later in Sept as I have been waiting on my replacement OSG diff to turn up. I am ditching the ported OEM intake and have installed the DMS intake with a 78mm TB. The 3.2 signed off at 7600rpm it still revved happily to over 8000rpm but didn't really make any power so the restriction was still the intake, Justin has been making good power up to 8400rpm with this intake.
the cars with this type of setup in Japan state that they are making 360hp to 380hp, if I hit 350hp I would consider this more than successful in my 1200kg car
 
scammy said:
What would you like to know, I have a 3.2 with the SOS cams which are not much different to the Comptech cams. I blew the head gasket on this engine at the track so that's being rebuilt now and going into something else with hotter cams again and a ITB setup so stay tuned on that one.
So in the meantime we built my original 3.0 into a 3.1 with a TODA piston kit and have the ported heads to 3.2 spec with SOS valve kit and the SOS cams going on this block its fully balanced and all new bearings etc etc,etc.
The 3.2 with a stock block and ported heads and intake/TB with those cams and a link ecu ran at 301hp and was significantly quicker than a stock 3.0 with normal bolt-ons.
The 3.1 is going back in the car later in Sept as I have been waiting on my replacement OSG diff to turn up. I am ditching the ported OEM intake and have installed the DMS intake with a 78mm TB. The 3.2 signed off at 7600rpm it still revved happily to over 8000rpm but didn't really make any power so the restriction was still the intake, Justin has been making good power up to 8400rpm with this intake.
the cars with this type of setup in Japan state that they are making 360hp to 380hp, if I hit 350hp I would consider this more than successful in my 1200kg car
Click to expand...

Cam, this is super helpful. I will need to read this a few times to get it to sink in, but I like the storyline. Net net, built motor and upgraded intake/exhaust can get you north of 300 hp without having to go FI. That was my real question...what can be made without FI. Take care. M
 
If you want a naturally aspirated benchmark that does not take you into the stellar RPM range, the S2000 F20C engine has a specific horsepower of around 120 hp/litre at a nudge over 8000 RPM which would be equivalent to 380 hp on a C32 if you kind of respect the original RPM limits. Trying to achieve outputs much beyond that and you will be into cranking up the RPM. The Ducati Panigale red line is somewhere around 12,000 RPM and most of the 600 cc sport bikes seem to be in the 14,000 RPM range. The Panigale generates an absolutely heroic specific horsepower (approx. 160 hp / litre crankshaft); but, with a mind buggering oversquare ratio of 1.86. The C32 is a piddling 1.15 over square in comparison so will unlikely ever achieve the volumetric efficiency and specific horsepower afforded by what must be massive valve area on the Panigale. In order to manage what must be huge valves at that elevated RPM the Panagle has a desmodromic valve system which I am going to guess would pretty much preclude a VTEC system. I don't think there would be enough space to fit all the required stuff in there.

To address your original question, the C30 / C32 is already at a place where additional horsepower gains are not going to be easy. The Honda F20C has a bore x stroke that is consistent with the C30/C32 and probably represents a realistic specific upper horsepower range unless you are prepared to crank up the RPM. Getting to or above the F20C specific horsepower range is going to be time consuming and likely really expensive. It is pretty clear why forced aspiration has de facto become the solution for more horsepower on a C30/C32 - it may not be cheap; but, I can pretty much guarantee that it will be cheaper.
 
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Old Guy said:
If you want a naturally aspirated benchmark that does not take you into the stellar RPM range, the S2000 F20C engine has a specific horsepower of around 120 hp/litre at a nudge over 8000 RPM which would be equivalent to 380 hp on a C32 if you kind of respect the original RPM limits. Trying to achieve outputs much beyond that and you will be into cranking up the RPM. The Ducati Panigale red line is somewhere around 12,000 RPM and most of the 600 cc sport bikes seem to be in the 14,000 RPM range. The Panigale generates an absolutely heroic specific horsepower (approx. 160 hp / litre crankshaft); but, with a mind buggering oversquare ratio of 1.86. The C32 is a piddling 1.15 over square in comparison so will unlikely ever achieve the volumetric efficiency and specific horsepower afforded by what must be massive valve area on the Panigale. In order to manage what must be huge valves at that elevated RPM the Panagle has a desmodromic valve system which I am going to guess would pretty much preclude a VTEC system. I don't think there would be enough space to fit all the required stuff in there.

To address your original question, the C30 / C32 is already at a place where additional horsepower gains are not going to be easy. The Honda F20C has a bore x stroke that is consistent with the C30/C32 and probably represents a realistic specific upper horsepower range unless you are prepared to crank up the RPM. Getting to or above the F20C specific horsepower range is going to be time consuming and likely really expensive. It is pretty clear why forced aspiration has de facto become the solution for more horsepower on a C30/C32 - it may not be cheap; but, I can pretty much guarantee that it will be cheaper.
Click to expand...

Thank you for the fact-filled post, Old Guy. Much appreciated.

Seems like I have some reading to do.
 
Anyone know what cams Acura used in their NSX powered Spice racer from the 90's? Was it a Comptech derivative? I think this engine put out around 450hp.
 
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Guys I'm on holiday for a couple of weeks however if it's any help with the numerous discussions with TODA and our playng around with three NA engines, TODA state a complete build from a 3.0 to a 3.5 that makes 450hp NA with ITB's for the intake and with every supportive mod they have so take that for what it's worth, assuming the engine is balanced and with all the porting and valve upgrades to the heads etc so with a start base of 260hp I sort of work that out with the mods I've done to be about 12.5hp per 10cc (with TODA pistons, OEM pistons maybe only 10hp per 10cc) so the increase in displacement is worth around 75hp from a 3.0 to a 3.5L or my 3.1 build 12.5hp and supportive mods make the rest; cams maybe 25hp (maybe 5 to 10 hp more with TODA cams over my SoS versions, Chris Wilson from SoS has stated the same) ECU maybe I5hp and intake which includes valves etc to be 30hp, balancing 20hp, TODA crank 10hp. This is obviously not scientific however based on the numerous setups we have been playing with is sort of ball park to what we have experienced. Working that backwards we are doing the 3.1 kit with OEM but balanced crank and DMC intake and are hoping for 350hp which if you use my assumptions I actually could get close to 370hp but I have SOS cams so minus 5-10hp and intake minus 5-10hp and crank 10hp so my build should hit 350hp which matches similar builds in Japan and they normally dyno higher. hope that makes sense after you guys have used your calculator a few times :-)
 
Speedmaster said:
So, as I try to better understand options for getting more HP out of my C30a, I keep going back to wondering why we simply don't put in "hotter" cams, and proportionately increasing capacity on the intake and exhaust.

Then, it occurred to me, this is not a Fiat. And, I am not still driving my X 1/9 with a larger Weber carb and a hotter than stock cam.

So, I am curious. Why don't we do just that? Don't cams afford longer valve position times (more flow in/out)? Wouldn't adding a higher-flowing intake and exhaust allow for those longer "open" times to add more HP?

I am no engine builder so I am sure I am missing something basic here.
Click to expand...

I spent years researching NSX cams lol. Short answer: the stock flow characteristics of the C30/32 are already very efficient, so cams don't add much. Comptech found that adding lift did little for power on stock internals. Cams only come into play with modified engines. RPM increases over 8,000, engine management, displacement changes, ITB, etc. are all factors where cams can add power. Look at the TODA C35B. Mostly race engine stuff.
 
Speedmaster said:
So, as I try to better understand options for getting more HP out of my C30a, I keep going back to wondering why we simply don't put in "hotter" cams, and proportionately increasing capacity on the intake and exhaust.

Then, it occurred to me, this is not a Fiat. And, I am not still driving my X 1/9 with a larger Weber carb and a hotter than stock cam.

So, I am curious. Why don't we do just that? Don't cams afford longer valve position times (more flow in/out)? Wouldn't adding a higher-flowing intake and exhaust allow for those longer "open" times to add more HP?

I am no engine builder so I am sure I am missing something basic here.
Click to expand...

Because Honda engineers were no dummies. VTEC allowed effectively two different cams to be used. Each cam profile was tuned according to the other engine design parameters, with the goal of having an emissions-friendly, everyday-driveable engine with a broad torque curve up until a 8k redline.

Now, you change other parameters such as, intake, exhaust, valve sizes, redline, fuel (e85?), compression ratio, etc, and now the cam profiles are no longer "optimized." Sure, they are "good enough" for most people, but if you are chasing power, it is easier to change the turbos than cams. Cams are expensive, time-consuming to change, difficult to degree, and there are other practical limitations like piston-valve clearances that limit how much you can change the cam profiles.

It all comes down to how much money do you want to spend and is it worth it to you?
 
Speedmaster said:
Which cams did you use?
Click to expand...
the 3.1 engine we have SOS NA cams, the 3.2 we have some Franklin cams with some higher lift than the SOS items so probably comparable to Spec C TODA's
My point is he has had most of the gains with his other mods and the cams will help but not do too much more without intake to help them
 
scammy said:
the 3.1 engine we have SOS NA cams, the 3.2 we have some Franklin cams with some higher lift than the SOS items so probably comparable to Spec C TODA's
My point is he has had most of the gains with his other mods and the cams will help but not do too much more without intake to help them
Click to expand...

Ah, that makes sense, 'Cam. Thanks for clarifying.
 
Speedmaster said:
Ah, that makes sense, 'Cam. Thanks for clarifying.
Click to expand...
I should have said "intake and an aftermarket ECU", we found that the ECU and tune makes the most gains and combine that with any mods you start to see increases because the mods are maximized which is why he wont see huge gains until his next steps. However do enjoy his journey as lots do
 
Am I the only one marveling at a guy named cam...talking about cams....:biggrin:
 

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