1001 replies to this topic

[Jamz14]

Just thought Id start the thread seeing how I just received the email announcing the results from all the 1.6 testing. Comments and opinions sure to begin flying.

 

The deburring and STR blending numbers look to be greater than what everyone was saying.

[Jamz14]

August 12, 2015

 

Dear Spec Miata Stakeholders:

 

One of the projects the Mazda/NASA/SCCA Spec Miata Group embarked on was development and testing of potential changes to the 1.6L NA Spec Miata. The following is a summary of the project protocol, developed and approved collectively by the group and funded by Mazda for the overall improvement of the class.

 

Recognizing the unique challenges that the smaller engine provides to the balance of performance (BoP) of Spec Miata, the group developed the following protocol to evaluate performance modifications.

 

Methodology: SCCA oversaw testing on a DynoJet Chassis dyno at Jesse Prather Motorsports (JPM), in Topeka, Kansas, to compare each modification. JPM performed all performance modifications to the test vehicle. SCCA's Club Racing staff verified compliance and results.

 

Control components: All cars used had a leak down and compression check performed to ensure consistent bottom end performance. All cars had fresh fluids in the engine, transmission and differential. All cars used the same octane fuel. The cars used the same rolling wheel/tire combination and tire pressure.

 

A 1999 Mazda Miata in its current specification and restrictor was used as the baseline car. The baseline car was a representative example of a competitive Spec Miata optimized to the engine preparation rules and verified as compliant to the new (2015) cylinder head regulations. The testing protocol was as follows:

-Engine warmed to operating temperature.

-Car rolled the dyno for 3-5 minutes to warm drivetrain fluids.

-All dyno pulls were done in 4th gear.

-Pulls were made until the power curve dropped off (or stabilized over multiple pulls). The best run was saved as the baseline for that configuration.

 

1.6L NA Testing

 

-A crate motor was supplied by Mazda. The cylinder head from this engine was installed in the test car, utilizing a seasoned bottom end, along with the Springfield Dyno exhaust, adjustable fuel pressure regulator and a cone-style intake. Following the process described for the 1999 car, the 1.6L car was tested separately, but cumulatively, with the following modifications:

1.New crate motor head as supplied by Mazda (unmodified).

2.Configuration 1 plus permitted plunge cut and 1.5mm blending plus valve unshrouding

3.Configuration 2 plus a Jackson Racing header.

4.Configuration 3 plus adjustable cam gears.

5.Configuration 4 plus mill cylinder head to achieve a compression ratio as close to 10:1 as possible without risking valve interference.

6.Configuration 5 plus additional STR blending to 3mm.

-The tests were performed from Mid-February through late March, concluding on March 31.

 

 

The test data have been shared with the SCCA Spec Miata Advisory Committee (SMAC) and NASA. These data can be used for potential BoP adjustments. This is on the current SMAC agenda for its call August 19.

 

The Spec Miata Group is sharing this information for several reasons. First and foremost, the Group wants the process to be transparent to the community at-large. Second, we want the community to have the opportunity to provide the sanctioning bodies with input as the data are evaluated for potential changes. Finally, we found the data enlightening, and felt that you would as well.

 

To provide input to the rules-making bodies, please submit letters to www.crbscca.com for SCCA and/or johnmueller@drivenasa.com for NASA.

 

For the sport,

 

Eric Prill, SCCA Vice President and COO

John Doonan, Mazda Motorsports Director

John Mueller, NASA Spec Miata National Director

Jim Wheeler, SCCA Club Racing Board Chairman

John Bauer, SCCA Club Racing Technical Manager

David Cook, Mazda Motorsports Business Development Manager

Steve Sanders, MAZDASPEED Motorsports Development Manager

Mike Allen, MAZDASPEED Motorsports Development Specialist

[Rob Burgoon]

Thank you Mazda!!

 

 

So... what's better?  

 

1. A pipey 1.6 that makes the same peak power as the 99, but sucks below 6000 and a little lighter than the 99  (config 6)

 

or

 

2. A 1.6 with config 3 and less weight to make up the gap?

[Rob Burgoon]

Just thought Id start the thread seeing how I just received the email announcing the results from all the 1.6 testing. Comments and opinions sure to begin flying.

 

The deburring and STR blending numbers look to be greater than what everyone was saying.

 

Not so fast, they illegally unshrouded valves too for that step.

[Jonathan Davis]

Did they do any AFM tuning on the 1.6? Those baseline numbers seem low to me...

[Rob Burgoon]

Should we request AFM delete and ECU for config 7?

[Jim Drago]

this should be interesting...

[ECOBRAP]

Did they do any AFM tuning on the 1.6? Those baseline numbers seem low to me...

 

Agreed, seems low. What about spark timing?

[Jamz14]

this should be interesting...

There is a old story about a goddess named Eris. She threw a golden apple into the wedding party of Peleus and Thetis. That story came to mind when drafting this topic.

[Steve Scheifler]

Did they do any AFM tuning on the 1.6? Those baseline numbers seem low to me...

I'm confident that JPM did at least the common tuning, but yea, from what I've been told if config 2 amounts to what is currently allowed then it seems very low compared to commonly quoted numbers, absolute and relative to the NB. The newest head casting may be part of that, but not all of it.

[Tom Sager]

Anyone know what kind of dyno?  The low HP numbers on the '99 don't seem to match the strong torque number at least compared to what I've seen on some dynojets.  Conversely the 1.6 in config 2 (prepped head) doesn't get anywhere near a good 1.6 torque number.  That right there would have caused me to stop.  They used a complete probuilt '99 but didn't do the same for the 1.6 as it was a street car bottom end?  That's apples and oranges to me.  

 

Might be useful for evaluating the 1.6 upgrades but as a comparison 1.6 to '99 it doesn't look correct.  

 

edit:  Ok it says a Dynojet was used.  Fishy looking numbers.  

[Tom Hampton]

Did they do any AFM tuning on the 1.6? Those baseline numbers seem low to me...

Agreed.  Also peak-HP occurs well down the RPM range (6500).

[Tom Hampton]

Anyone know what kind of dyno?  The '99 HP numbers on the '99 don't seem to match the torque number at least compared to what I've seen on some dynojets.  The '99 makes very good torque on this dyno but the HP is lower than you'd expect with the torque it makes.  The 1.6 in config 2 (prepped head) doesn't get anywhere near a good 1.6 torque number.  That right there would have caused me to stop.  They used a complete probuilt '99 but didn't do the same for the 1.6 as it was a street car bottom end?  That's apples and oranges to me.  

 

Might be useful for evaluating the 1.6 upgrades but as a comparison 1.6 to '99 it doesn't look correct.  

 

edit:  Ok it says a Dynojet was used.  Fishy looking numbers.  

It says "DynoJet Chassis dyno at Jesse Prather Motorsports (JPM), in Topeka, Kansas".

[Duane Polsley]

Does config #5 include the Header? If not, why not try both?

[Tom Hampton]

Does config #5 include the Header? If not, why not try both?

yes, it includes all previous configurations.

[davew]

I have spent all of 5 minutes looking at the table above. I am still going to stand by my long held belief that a 100% built 1.6 would be competitive with a 100% built car of any year. Although I seem to be in the minority on that. With that being said: here is my 5 minute opinion. I reserve the right to change my mind.

 

This stock head is pretty good, since there was only a 3hp/2torque (Config #2) increase with the current 2015 head rules. My question would be was the compression ratio optomised for config #2? I am going to hope so, but that is an assumption that could throw all the numbers up for grab.

 

The header adds roughly 5 and 5

 

The compression adds 5 and 4

 

The STR adds nothing of consequence.

 

IMHO adding both the header and the compression would definately make the 1.6 an overdog.

 

Adding either a header or compression may make the 1.6 a slight overdog. Forcing a bunch of people to build new cars. At least to experiment with.  Good for me, bad for the class. If either option is to be considered, some weight should be put back on the car. If nothing else to make it easier for the larger guys to get in a 1.6 car.

 

Both compression and a header have issues. First is price. Pulling the head, doing all the calculations. Doing a legal/optimum valve job and then milling to max compression is going to be a $1200 machine shop charge. Add in a gasket set, fluids and labor and you have a $2000 bill if done by a shop. A header could be purchased for $150-$450 with minimal installation charges. Header wins the cost issue.

 

Next is availability. The heads already exist and the engine builders could get a lot of heads done in a short period of time. How many 1.6 headers are available? Is the thought to pick a particular header and require only that part? Or do we spec the dimensions and tubing on the header? But does header builder A make a better header than builder B? Will we have "the header of the week" for a while, as things sort out?

 

How about enforcement? We already have the valve job specs. We already know how (even if we rarely do) to verify compression ratio. Enforcing a different compression ratio is as easy as changing the spec in the GCR. Enforcing the dimensions of an aftermarket header is going to be tough. Opening the rule to "any header" is going to be expensive.

 

My personal opinion has not changed. Until a 100% 1.6 car is built and raced by a proven driver. At various tracks. Change nothing on the engine. I would still allow everyone onto the same suspension components. But that horse has been beaten to death already.

 

I applaud the efforts made by the SM group. I hope that whatever is decided, will be well thought out. Taking into account what is best for the class as a whole. Not just what is best for one group (engine). Factors like cost, availability, enforcement, class stability all need to be included in the discussion.

 

To address the comments about the raw numbers. Let me point out that every EVERY dyno reads different. I had a computer crash and had to get new dynojet software. Ever since, I have lost a couple hp. Compare these results to these results only. Please do not compare them to what you got last year. Or what has been posted on this and other websites previously. Like the official scales are official. Even if they are wrong. These numbers are what we have to live with.

 

Thank you to all involved in this endeaver.

dave

[Rob Burgoon]

DaveW, is valve unshrouding legal?  I didn't think it was, and it's part of config 2.

[chris haldeman]

Yes rob it is

[Johnny D]

Rob, I don't think the Jackson Racing Header is legal either.
Just Saying.
J~

[Rob Burgoon]

Yes rob it is

 

Oh duh.  For some reason I was thinking "blend".