Jeff N.
08-14-2005, 10:53 AM
Have about 280 miles on the new engine. For those of you following, this is a clone of the Metric Mechanic 3.7 "sport" engine. I have the MM ported head and cam and just installed a short block with the 95mm overbore pistons that bump the compression to 10:1.
Here's the bottom line so far. I like it. While it's hard I think to tell the sum of the improvements from having a fresh bottom end vs. the bump in compression and increase in displace, the end result it really good. Is this a tire burning type upgrade? Nope. Not that. But this is the motor that I've wanted to have for a long time.
The car has big time roll on the freeway. 3rd gear pull is stout and the car gets up and really walks away nicely at 75mph. Hit 4th and it just keeps on going. I'm still keeping the revs below about 5200 RPM or so I can't give an upper end report but I'm working it that way. Off cam, where it was really sluggish before, the car is much more driveable. Doesn't have the big torque bulge the stock motor has at 3k RPM but you don't feel like your driving a jekyll and hyde car like it was before. Tip in power is sufficient at 2k RPM and if you want to get up and go, drop it a gear or two to hit 3.5k+ on the tach. There is still some "waiting on the cam" effect from 2.5k to 3.5k, especially when you compare it to say...Martin's car.
As many of these changes have been incremental, it'd be fun to go back and drive a stock 535 now to see how all this plays out side by side.
I think the big question I have right now it where the powerband is situated. By design, the MM cam comes on a 3.7k and keeps going. I'm not sure that where you really want for a city/street car. I'm going to let the motor break in and drive it for a while but there's still a thought in the back of my head to swap the current cam for a schrick 282 which should drop the start of the torque curve down to about 3k. I will have to give kudos to the MM cam in that the car idles dead smooth and runs very well overall. You have no clue the motor's been modded at all idle.
With the new engine, the 3.73 gears in the back feel maybe a little short. I could see a really nice combination being the schrick cam and the 3.64 gears vs the 3.73 gears. Not that I'm complaining mind you! :)
So...here's the current setup:
10:1 forged pistons, MM variety, with 92 ---> 95 mm overbore.
Stock stroke
Ported head from MM
MM "rally cam", low overlap, high lift and duration about 275 or so??
MM adjustable cam gear, cam at +4 degrees at the moment
Port matched intake
Balanced engine assembly
Racing King (Pro Flow) MAF conversion
19lbs Mustang injectors
Stock exhaust from manifolds back
22lb E28 flywheel with E28 clutch
3.73 LSD (shortened from 3.46 stock gears)
Stock chip
Still to dos
Finish up the break-in
Try tinkering with some other chips to see what happens
Try some g-tech runs to check output
Consider having the flywheel lightened up to about 14lbs or so (should have done that during the motor job...my bad)
Consider installing a wideband o2 sensor (LM-1 kit from Innnovative)
Enjoy the heck out of it!
More reports as things progress.
Cheers!
Jeff
Here's the bottom line so far. I like it. While it's hard I think to tell the sum of the improvements from having a fresh bottom end vs. the bump in compression and increase in displace, the end result it really good. Is this a tire burning type upgrade? Nope. Not that. But this is the motor that I've wanted to have for a long time.
The car has big time roll on the freeway. 3rd gear pull is stout and the car gets up and really walks away nicely at 75mph. Hit 4th and it just keeps on going. I'm still keeping the revs below about 5200 RPM or so I can't give an upper end report but I'm working it that way. Off cam, where it was really sluggish before, the car is much more driveable. Doesn't have the big torque bulge the stock motor has at 3k RPM but you don't feel like your driving a jekyll and hyde car like it was before. Tip in power is sufficient at 2k RPM and if you want to get up and go, drop it a gear or two to hit 3.5k+ on the tach. There is still some "waiting on the cam" effect from 2.5k to 3.5k, especially when you compare it to say...Martin's car.
As many of these changes have been incremental, it'd be fun to go back and drive a stock 535 now to see how all this plays out side by side.
I think the big question I have right now it where the powerband is situated. By design, the MM cam comes on a 3.7k and keeps going. I'm not sure that where you really want for a city/street car. I'm going to let the motor break in and drive it for a while but there's still a thought in the back of my head to swap the current cam for a schrick 282 which should drop the start of the torque curve down to about 3k. I will have to give kudos to the MM cam in that the car idles dead smooth and runs very well overall. You have no clue the motor's been modded at all idle.
With the new engine, the 3.73 gears in the back feel maybe a little short. I could see a really nice combination being the schrick cam and the 3.64 gears vs the 3.73 gears. Not that I'm complaining mind you! :)
So...here's the current setup:
10:1 forged pistons, MM variety, with 92 ---> 95 mm overbore.
Stock stroke
Ported head from MM
MM "rally cam", low overlap, high lift and duration about 275 or so??
MM adjustable cam gear, cam at +4 degrees at the moment
Port matched intake
Balanced engine assembly
Racing King (Pro Flow) MAF conversion
19lbs Mustang injectors
Stock exhaust from manifolds back
22lb E28 flywheel with E28 clutch
3.73 LSD (shortened from 3.46 stock gears)
Stock chip
Still to dos
Finish up the break-in
Try tinkering with some other chips to see what happens
Try some g-tech runs to check output
Consider having the flywheel lightened up to about 14lbs or so (should have done that during the motor job...my bad)
Consider installing a wideband o2 sensor (LM-1 kit from Innnovative)
Enjoy the heck out of it!
More reports as things progress.
Cheers!
Jeff