Back in Winning Blue. Our 'new' Project Blue!

Miata Parts, Intakes, Superchargers, Headers, Exhausts, Shocks, Springs, Sway Bars, Brake Kits, Autocross and track mods.
Chuck H
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Joined: Fri May 18, 2012 6:28 am

Re: Back in Winning Blue. Our 'new' Project Blue!

Post by Chuck H »

My guess would be that the 2.5L motor can use a surprisingly large header, especially if it's tuned to favor the high RPM range, since the bigger motor doesn't seem to be lacking for low and mid range torque.

I have a spreadsheet that cranks through A. Graham Bell's calculations for primary size for headers, and with the 2.5L engine specs tuned for 7000 RPM peak power, it comes up with 2.125" primaries about 24" long. Not sure how big the exhaust ports are on the 2.5L head, but 2-1/8" primaries seem huge. This might actually be a good excuse to try a stepped header design with 1-3/4" or 1-7/8" primaries for the first half of the length, then stepping up to 2" tubing for the remainder of the length and feeding the collector. :twisted:
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Brian
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Re: Back in Winning Blue. Our 'new' Project Blue!

Post by Brian »

Chuck H wrote:My guess would be that the 2.5L motor can use a surprisingly large header, especially if it's tuned to favor the high RPM range, since the bigger motor doesn't seem to be lacking for low and mid range torque.

I have a spreadsheet that cranks through A. Graham Bell's calculations for primary size for headers, and with the 2.5L engine specs tuned for 7000 RPM peak power, it comes up with 2.125" primaries about 24" long. Not sure how big the exhaust ports are on the 2.5L head, but 2-1/8" primaries seem huge. This might actually be a good excuse to try a stepped header design with 1-3/4" or 1-7/8" primaries for the first half of the length, then stepping up to 2" tubing for the remainder of the length and feeding the collector. :twisted:
Here is what an NC header looks like with 2 inch primaries.

This is a test unit from our NCLIGHT Project, from many years ago, part of the reason that car makes 270 hp at the wheels (project linked from our front page for those seeking to read the history). But this is a bit too much for the comparatively low compression mild cam factory 2.5 motors most are using for conversion.
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Brian Goodwin
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Chuck H
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Joined: Fri May 18, 2012 6:28 am

Re: Back in Winning Blue. Our 'new' Project Blue!

Post by Chuck H »

I see that you're already way ahead of me with all these header experiments! :D
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Brian
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Re: Back in Winning Blue. Our 'new' Project Blue!

Post by Brian »

Back from 10 days on the road in Project Blue, including a full weekend of Laguna Seca Fast Groups A and B!

A real testament to this package that my wife and I could live out of this car for 10 days on the comfort of our Ohlins coilovers and Progress Sways yet still run with some of the fastest stripped out race cars of the A and B groups at Laguna Seca....and then comfortably drive another 437 miles home Sunday night! Worst thing that happened all weekend was slight issue with the gas gauge and I nicked a finger.

My heartfelt gratitude for the efforts of Rick and Keith and Lisa and Doug and everybody else that made it such an amazing event. Given the record number of attending owners I think it a miracle it went so smooth, a real tribute to both organizers and the kind demeanor of Miata owners generally. Thanks to all those who stopped in to say hello.
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Brian Goodwin
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Brian
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Re: Back in Winning Blue. Our 'new' Project Blue!

Post by Brian »

Thanks from Laguna!
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Brian Goodwin
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roadster_nh
Posts: 47
Joined: Mon Jun 28, 2010 5:19 pm
Location: DFW

Tomei ?

Post by roadster_nh »

Brian, are you still running the Tomei LSD on the blue car? If so, what's your long term review/opinion?
2003 LS FFS
Brian
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Re: Back in Winning Blue. Our 'new' Project Blue!

Post by Brian »

Yes, it served us VERY well during the Laguna Seca weekend. Works great for Autocross too. Where it won't serve some folks well is pure daily driving. If you don't race, you don't need this much lockup rate. When I put hard daily driver tires on the car, like 280 or harder, this unit locks up enough to make some noise in first gear starts when the wheel is not pointed straight (like when you take off after stopping to make a right turn at a stop light). The noise is not the unit so much as it is the tires (so much lock rate from the unit that hard tires scrub the pavement in slow turns). If you have some 200 or softer treadwear there is enough grab of the surface that you don't get this effect. So, for the aggressive driver this is a great unit, but if not racing on the weekends then even this 12 disc unit is overkill.

To sum it up, for the MONEY, this unit is a bargain for the racers out there.

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Brian Goodwin
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roadster_nh
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Re: Back in Winning Blue. Our 'new' Project Blue!

Post by roadster_nh »

Thanks Brian. So is the lockup rate for the Tomei similar to the OSG and Quaiffe units? My MX5 is not a daily driver and will ultimately be prepped for STR and some track days.
2003 LS FFS
Brian
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Re: Back in Winning Blue. Our 'new' Project Blue!

Post by Brian »

The OsGiken is even more with 24 discs, this unit is 12 disc, the old MazdaSpeed unit was just 7 disc, these are all clutch disc style units. The Quaife is a gear unit, totally different beast, doesn't have the scrub of the Tomei and OSGiken when hard tires are on but will 'click-click' when engaging (and it does ZERO if you lift one wheel in turn).
Brian Goodwin
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Re: Back in Winning Blue. Our 'new' Project Blue!

Post by Brian »

More Dyno fun!

This was additional testing before Laguna event briefly touched upon above. Had folks ask me what happens if we use standard PPE Long Tube on the 2.5 motor? The result we have seen with customers is that peak power drops off about 20hp from what we got with our prototype header, because the 1.5 inch diameter primaries are just way too small for 2.5 motor and choke the top end (1.5 inch primaries also too small for 2.0 motor too if you are focused on high end numbers, see results we have posted for 2.0 motor header shoot out between PPE and RoadsterSport Max Power back on page 9 of this thread). For comparison, we use more than 1.5 inch primaries on the little 1990 Miata with just 1.6 liter motor.

Okay, knowing 1.5 inch primary version of PPE is too small to give us the results we wanted to see, we called PPE and had them make us a bigger primary version of their venerable long tube MX5 header. The size we picked for the primaries for this new version of the PPE is what all our testing has made us believe is the ideal size for 2.0 liter, and we figured we would still get good torque with perhaps slightly less peak hp on 2.5 motors....and that's precisely what we got below.

Blue and Red lines in the dyno graph below are the BIG tube prototype PPE and the Green line is best with our new prototype shorty shown a few pages before (and we left the much lower 2.0 run on the graph too just to show again how far we have come from 2.0 numbers). The peak HP number does drop from 200 to 194, but we GAIN more area under the low to mid range RPM TORQUE curve with a new BEST peak torque number of 199. Also not a surprise is that the shorty header does slightly better torque in the very upper end. So, do you want best PEAK Hp or best mid range PEAK torque? To sum it up, we got 200hp and 195 torque with our prototype shorty header, and those numbers neatly flip to 194hp and 199 torque for the bigger diameter long tube. If you think about it, it can be real hard to pick between those two pretty interchangeable options, so we will give you BOTH options! We are having PPE put this new bigger primary long tube into production for our customers as the "Good-Win Racing Edition" because I am convinced that those wanting a long tube need this bigger primary version for best results on the 2.0, and these results on 2.5 show it still does a solid job for 2.5 too. More testing fun to come soon.
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