Cam Design (Or lack thereof) for the MZR DISI

I pulled this over from a post I had a while back, while I was working with Web on what I would consider actually useful cam grinds for us and working with Teo on tuning a set of "big" cams Piper had sent him to try in his AWD speed 3.. I stopped all Mazdaspeed development of any kind last year, so nothing really came to fruition, though I'd love to start seeing people run actual cams, just for the major increase in efficiency.

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Without getting into a theory vs practive debate on the topic, I'd just like to post some specs from some of the most prolific I4 Turbo cams on the market today.

Intake/Exhaust ADV Dur ; Dur@.050" or @1mm ; Max Lift ; Centerline

Evo X - GSC S2 (VVT and COB): #1 cam for street and track evo X, stock displacement up to 2.3L

274/274 ; 230/230@1mm ; 11.2mm/11mm ; 128(variable to ~110)/115

Evo 9 - GSC S3 (VVT): #1 cam for street and track evo 9 mivec heads, stock displacement up to 2.2L, newer R2 cams starting to take over for 2.2-2.4L strokers.

280/280 ; 236/236@1mm; 11.7mm/11.4mm ; 128(variable to ~110)/115

Evo 9 - GSC R2(VVT): #1 cam for street and track evo 9 mivec heads, 2.2L+ displacement

274/274 ; 236/236@1mm ; 12.1mm/11.9mm ; 128(variable to ~110)/115

Honda B-series - GSC T1 Turbo(high lobe only) One of the absolute best turbo cams on the market for one of the most common I4's on the planet to turbo.

288/276 ; 260/254@1mm ; 12mm/11.5mm ; 109/115


Honda K-series -Prayoonto S2: One of the top turbo cams for the K-series from 2.0-2.6L strokers.

305/300 ; 235/230@.050" ; 13.46mm/11.49mm ; 110/110

Nissan SR20 N1: Factory upgrade for SR20 guys, thought to be an NA only cam, but has worked great on BT cars as well. Among the more aggressive turbo cam setups.

324/300 ; 255/252@.050" ; 12/11.9 ; 104/109

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Teo's Piper Cams

288/276 ; 236/236? (I saw you mention 224 but didn't see that anywhere) ; 11.73mm/11.43mm ; ~128(variable)/115 (I believe Teo may have tweaked the center lines from this though)

I believe Teo is also currently limiting his map to 20* VVT ADV just to be extra safe with the intake valve to piston clearance, which will also effect the spool.
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Now, you have to do some small conversions since some of the duration measurements come from the manufacturer @1mm (a slightly larger part of the lobe) and some @ .050" (a slightly smaller part of the lobe), and you'll also have to convert some between the bucket setup like us vs rocker setup like most others, but overall you can see that Teo is right in line with the smaller side of the available cams out there, even for a turbo car. That, coupled with his free-flowing exhaust and proper turbine/housing setup, should make for a great combo.

Yes, they will really shine with another 500+rpm to work with (which will be coming), but still should be very nice at 8k.

Lastly, I believe rangerGT used to run Crower S3's in his 2.3 Duratec, which he said were very streetable, but I believe he went to a bigger cam after that, so he may have some input as well.

The Crower S3's are 284/276 ; 236/228@.050" ; 11mm/10mm

 

I've played around with fitting 2.3 Ecoboost cams into our head. They fit with some work but running an exhaust cam in place of the intake is kind of taking a step backwards. Still waiting for them to have more aftermarket options other than the Ford Performance cams.

I've talked with more than a handful of companies on trying to find a manufacturer for an intake blank to have my own grind made but either no one knows who cam make a blank with the HPFP extension or won't tell me.

As of right now I'm probably going to pick up a set of Piper S2 cams while the euro is still weak.

 

What about the SP63 ones? (Perhaps there's some blatantly obvious reason I'm oblivious to; if so, my apologies!) LOL

Cams are great, but I think they're really a lot more helpful on N/A motors. For us, if we want to change our power delivery curve, we can do so with a combination of turbo selection and tuning. If your turbo has enough flow rate, you can pretty much put as much power as you want, and where you want it (depending on surge line, of course), using boost and timing levels, right?

 

Nothing wrong with them really. For me it's just that they're not aggressive enough in the ways I feel they should be. That and lots of people don't like regrinds and would rather something cut from a blank.

The piper cams are more along the lines of a "real" cam, though not perfect either IMO. With that said, the big ones were a huge help on Teo's car up top. As for not needing cams on a turbo car, I understand your thought process, but without getting too into theory, just look at all the rest of the I4 turbo cars... First engine upgrade, well before rods even, is the cams. It's just the fact that any time you can make the engine/turbo setup more efficient, you keep everything happier, while also making more power. Basically just "Work smarter, not harder" but for the engine.

 

SP63 cams are two things I don't want: regrinds, and expensive. The Piper S2 set comes to around $650 shipped and they're machined from new blanks. Plus Piper has the full specs published for them.

Performance cams will help any engine. Stock cams have to balance performance and emissions and that's a compromise. Most people don't realize it but our engine uses the same exhaust cam as all of the 2.0,2.3 and 2.5 MZR engines. Of course you can make power without upgrading them (we've seen it plenty of times on our platform alone) but that doesn't mean you're not leaving performance on the table. Milder grinds will pick up decent power across the whole curve over stock cams. Aggressive grinds will have huge gains on the top end over stock cams but sacrifice some low end performance. The reality of it is that no one makes a huge deal over our lack of cam selection because it almost doesn't exist.

Also, they allow you to make more power on a smaller turbo. Being able to flow more at lower RPMs means that you are less likely to run into surge. To keep things as simple as possible, gaseous flow into and engine = gaseous flow out of an engine. The more that you can cram in, the more there is to take out, and the more power that can be made.

Obviously there are other things that need to be considered like valve sizing, valve to bore ratios, port saturation points, piston clearance, etc. But as long as the head and valves aren't the limiting factor to flow, then cams will always provide good gains. Go back and read the Corksport white papers on their cams. Their lift specs were just about perfect for a stock head and valvetrain. It really is a shame they didn't get those to work.

 

Indeed. Hopefully they're just doing their due diligence, then will re-release them. I'd still wait another year after they drop before I'd use them, though. Always good advice for a new product, especially a very unique one

 

Very well said.

The only thing I would challenge is the CS cams. My major beef with just about every cam design for us is the low lift in all the profiles. Everyone talks about valve lift in terms of the point our stock ports/head become saturated/cannot flow any more... What few talk about is the fact that if you do go past that point for max lift, you are effectively lengthening the time the valve is open at the maximum efficiency of that head, which increases powers production quite a bit.

In simple terms, if we know our head flow tops out at 10.5mm lift(just an example) we don't want to have that as out peak valve lift because we're only at that peak airflow for a split second... We'd want more lift so we can enjoy that max amount of flow for the longest portion of the duration possible.

There's obviously only so much lift you can have and there's always trade offs, but for our purposes, I wouldn't run a cam under 11mm lift for any reason on our engines (if built and have valve relief Pistons) and would really prefer closer to 11.5+.

As a general rule, lift increases power across the rpm range and duration moves power to the right In the curve.

 

Agreed on all parts. Possible reasoning why they didn't go with a much higher lift than what they spec'd is they were afraid of piston clearance issues (unlikely), wear issues, or possibly compromising other parts in the valvetrain (springs, friction washers, valves). I'm not sure where coil bind is on stock springs but I don't see them having an issue handling more lift. Another reason for not going as high as possible on lift is that it can increase your ramp rates which can increase valve and valve seat wear (especially when paired with much stiffer springs) or float (if the springs aren't upgraded).

I was really hoping that 2016 would see another option or two come about but maybe that'll be 2017.

 

Thread necro! Just saw this referenced at the bottom of my MZR thread.

I've got a set of $200 regrinds in hand at lower lift higher duration that might be viable; engine sim seems to think so even factoring in stock head flow:
Assuming the stock engine makes 260///280, only swapping cams (assuming the stock turbo could flow enough), the power levels jump to ~355 torque @ 5k and ~365 horsepower @ 6500 (at the crank).

http://mazdaspeeds.org/index.php?threads/disi-mzresponse.457/page-2#post-21644

Stats are 220 duration for both sides, close to stock lift exhaust and .304 (7.7mm) lift intake (lower lift to avoid welding; grind only); headwork improves flow, but I don't think maximum lift is necessarily required depending on your power goals. Four digits? Absolutely.

Once I get someone to test them on a stock displacement engine I'll release the grind info, which Crower still has on file.

 

It's very wishful thinking that a 12* increase in duration will pick up 100hp. Especially when you're losing almost 70 thou lift.

 

Well these were reground by reducing the base circle, thus fattening up the duration on the stock curve, although I think some work was done to properly taper the intake side so that the grind is actually usable.
Also, sorry about that; my cam card says the durations are actually 223 intake and 225 exhaust (@ 0.050) with .304 lift intake and .322 lift exhaust.

It's entirely possible that I either put the numbers in the simulation wrong or the numbers I have are wrong as far as orientation to TDC goes. Time will tell.

 

I'm shocked no one has pointed out in this thread that corksport has re-released their cams. Intake .390" Total Lift 215.8 @ .050 Duration, Exhaust .354" Total Lift 204.2 @ .050 Duration.

 

I think it's because people are just waiting to see what happens. We remember the last CS cams debacle.

 

I don't! What'd they do?

Seems pretty standard for them to release something, it fails catastrophically, then the v2 or v3 comes around and it's a great product.

 

Long story short the cams were complete shit and no good so all of them had to be recalled. CS said the manufacturer didnt follow their exact specs and that's why they failed.

 

The exhaust cams weren't ground to spec for where the sprocket bolts to it. The lobes themselves were fine.

CS did their homework, they're the right amount of cam for a head that doesn't have port work. If you are looking for real power, you'll want more aggressive cams and headwork done.

 

I know CS did their homework. I wasn't trying to imply it was their fault if it came off that way. The manufacturer didn't produce them to there spec or quality.

 

If memory serves (might be wrong), the cams weren't hardened at all so the followers ate the lobes or something like that.

 

I think they were too short lengthwise and the sprokets couldnt tighten correctly

 

Just to clear things up here...
The original release of camshafts were not properly heat treated from the manufacturer despite their claims that they were so we recalled all the camshafts that had shipped to customers and provided them a $200 bonus of CS reward points along with a full refund for the headache. We resolved the hardness issue and got replacements. The replacements then had another issue so we lost faith in the manufacturer.
The most recent camshafts are with a new manufacturer with much more strict QA process. Our own QA process has also been improved significantly for this product. Every batch has one EX and IN camshaft sent out to a 3rd party testing facility to verify the hardness of each lobe and the fuel pump lobe. This is destructive testing FYI.
I assure you that the camshafts arriving at your door from CS are of the highest quality in performance, durability, and even packaging.