SC for MDX
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Subie Dubie
Joined: Feb 2001
Posts: 5,987
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From: PDX
SC for MDX
I don' t think anyone from the West Coast Meet mentioned this, but our guy from Comptech informed us that they were working on the SC for the MDX, and he said it would be awesome 
I think he also indicated it would develop more boost than for the CL/TL. Whoa, i could have one wild garage 
I think he also indicated it would develop more boost than for the CL/TL. Whoa, i could have one wild garage
Thread Starter
Subie Dubie
Joined: Feb 2001
Posts: 5,987
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From: PDX
Originally posted by Zapata
mike,
the new one is a 5speed which has been redesigned completely. Not sure how the old one is different.
mike,
the new one is a 5speed which has been redesigned completely. Not sure how the old one is different.
Safety Car
Joined: Aug 2002
Posts: 4,910
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From: So Cal
SC
It's easier to get more boost (safely) out of a bigger.. lower-revving motor. Case in point - S2000. That car doesn't start making power until 6.5K. Now... 5psi MAX at 9000 rpm... is like 0.5-1.5 psi in the 3K to 4K range... hence no low-end. On the CL-S and ultimately the MDX... you can have 5.5 psi at 6.8K and still have a decent 2-4psi in the lower-rpm areas. MDX... even better than that.
This is why the 5.0's (Mustang) have oodles of power at all rpm's considering their 5.5K to 6K redline.
Comptech (or other manufacturers) need to add some kind boost regulator (sort of what a wastegate does on a turbocharged application) to maintain the same boost condition over all rpm's.
But then... why would they listen to me?
Just IMHO.
This is why the 5.0's (Mustang) have oodles of power at all rpm's considering their 5.5K to 6K redline.
Comptech (or other manufacturers) need to add some kind boost regulator (sort of what a wastegate does on a turbocharged application) to maintain the same boost condition over all rpm's.
But then... why would they listen to me?
Just IMHO.
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Cost Drivers!!!!
Joined: Mar 2001
Posts: 19,392
Likes: 1
From: burbs of philly
Originally posted by Mike
That's cool! Anyone know how the MDX tranny differs from ours? Can we do a tranny swap or use MDX parts to harden our tranny?
That's cool! Anyone know how the MDX tranny differs from ours? Can we do a tranny swap or use MDX parts to harden our tranny?
To handle the additional horsepower and torque, the 2003 MDX receives an all-new, compact 5-speed, automatic transmission. This compact, efficient gearbox utilizes a super-flat torque converter and a 4-shaft layout that relocates the third gear clutch to reduce overall length by 60 mm over the previous transmission while increasing torque capacity. Furthermore, an innovative shaft center layout of the idle row gear reduces the amount of gear inclination during driving, thereby reducing gear noise.
This new layout relocates the third gear clutch from the countershaft to a new transmission shaft. The combination of the new layout and the adoption of a super flat torque converter allowed engineers to reduce the overall transmission length by 60 mm while increasing torque capacity to match the more powerful engine. The shape of the differential gear and the shape of the oil sump have been changed to reduce the collection of oil in the pan and separate the oil from the gears. This reduction in friction improves efficiency, thereby boosting performance.
Creative use of clutched idler gears permits the transaxle to provide five forward speeds with little more weight or bulk than a typical four-speed automatic. A one-way clutch is provided for first gear to smooth upshift quality. An ext'ra-capacity transmission fluid cooler is offered with the MDX's optional tow package to maintain acceptable lubricant temperatures during heavy-load conditions.
Creative use of clutched idler gears permits the transaxle to provide five forward speeds with little more weight or bulk than a typical four-speed automatic. A one-way clutch is provided for first gear to smooth upshift quality. An ext'ra-capacity transmission fluid cooler is offered with the MDX's optional tow package to maintain acceptable lubricant temperatures during heavy-load conditions.
Old timer
Joined: Dec 2000
Posts: 9,224
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From: .
Hmm, I've never considered an SUV as my next vehicle, especially as a performance vehicle. Maybe an '03 MDX with the supercharger would help counteract the weight of some ice and 24" rims.
Btw, is there any exterior make-over for the '03 MDX?
Btw, is there any exterior make-over for the '03 MDX?
Suzuka Master
Joined: Sep 2000
Posts: 9,431
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From: Woodstock, GA
Re: SC
Originally posted by allmotor_2000
Comptech (or other manufacturers) need to add some kind boost regulator (sort of what a wastegate does on a turbocharged application) to maintain the same boost condition over all rpm's.
Comptech (or other manufacturers) need to add some kind boost regulator (sort of what a wastegate does on a turbocharged application) to maintain the same boost condition over all rpm's.
The blower to be used on the CL and MDX will be a positive displacement unit (Eaton/Magnuson Gen IV M62) which moves 62 CI of air per revolution. So when under load it makes basically the same boost throughout the rev band. Boost can vary a little due to changing efficiencies of the engine at different RPM. But this is normally very little, maybe 1 PSI when running 8 PSI max.
So with this style blower there is no need to regulate boost, you get about the same amount throughout the rev band and the amount is dictated by the gearing of the blower pulley to the crank pulley and the displacement of the engine.
For example, we have a roughly 190 CI engine but since only half the cylinders fill for every rotation of the engine but the blower puts out the same amount of air every rotation we need to cut the engine CI in half to 95 CI.
Now let’s gear the SC pulley to a 2:1 ratio so that it turns at twice the speed of the engine. Therefore it puts out 124 CI per revolution. That is a ratio of 1.3, multiply this by 14.7 (ambient pressure) then subtract out 14.7 and you have a boost level of about 4.41 PSI. That would equate to a roughly a 25% gain in torque across the rev band.
Now go to a SC pulley to engine gear ratio of 2.5:1 and you end up with about 9.28 PSI, again, throughout the rev band. This would equate to a roughly 40% - 45% gain in torque all across the rev band provided deto wasn’t an issue and timing was the same.
Xe- For Better Hwy Vision
Joined: May 2001
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From: Valley Forge, PA.
I don't know, any major increases in PSI in an already high compression engine scares the crap out of me no matter how you look at it.
Not that it is impossible to regulate based on drive gear ratios as discussed above.
Not that it is impossible to regulate based on drive gear ratios as discussed above.
Thread Starter
Subie Dubie
Joined: Feb 2001
Posts: 5,987
Likes: 1
From: PDX
Originally posted by JRock
Hmm, I've never considered an SUV as my next vehicle, especially as a performance vehicle. Maybe an '03 MDX with the supercharger would help counteract the weight of some ice and 24" rims.
Btw, is there any exterior make-over for the '03 MDX?
Hmm, I've never considered an SUV as my next vehicle, especially as a performance vehicle. Maybe an '03 MDX with the supercharger would help counteract the weight of some ice and 24" rims.
Btw, is there any exterior make-over for the '03 MDX?
Racer
Joined: Aug 2001
Posts: 334
Likes: 0
From: Fort Worth, TX
Originally posted by Red Rider
The 2001 and 2002s have a 5 speed also, but are not affected it seems. Maybe because they were designed for the higher torque of the MDX (260 versus 232 on the TypeS )
The 2001 and 2002s have a 5 speed also, but are not affected it seems. Maybe because they were designed for the higher torque of the MDX (260 versus 232 on the TypeS )
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