1972 CSi Turbocharged, 6 Speed

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SoCalE9

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Jeff Tighe (Orange County) is currently performing restomod on my 72 CSi. Been at his shop for almost 3 years. Delayed because of covid. Just wanted to ask the forum if anybody else is doing similar restoration/modifications. Jeff is doing the job with the following:

S52 M3 motor with performance tuning from Bullet
High flow cat
Turbocharged with all plumbing and intercooler with dash mounted boost gauge
6 speed transmission
3.43 LSD
Jeff modified the suspension for adjustable shocks (all four corners)
Unibody strengthen/welded (stitched) at critical areas to handle the increased hp and torque
Larger brakes
Dual disk clutch

Change color to MBZ silver from polaris, Jeff had done one that was done with red interior in black (looks really good), but wanted a lighter color
Burnt red interior
Alpina steering wheel
Alpina wheels
European light bulbs
Power windows all around
Custom console to house the 6 speed shifter
New sapele wood trim

Thank you
 
Big Suspension Techniques sway-bars with poly bushings.
Black & Grey #53 Cocomats.


Using a Z4 shift platform?
Cut & weld top of original gear shifter to use an original spin on type.
Alternatively, make a custom gear shifter & thread to 1.5 x15mm.
Pet peeve is modern shift knobs in E9s, so out of place. Stealth is the key.
 
Yeah quite a big change! Jeff and I talked about the hp upgrade regarding the plus and minuses. Jeff having done an earlier S52 transplant into an E9 wanted to try out a turbo charged version. I guess my E9 is the guinea pig for this modification. Both of our concern was the amount of torque the body would be subjected to with increase. After lengthy discussions, the approach was to strengthen the body with as much welding of the seams at critical and non-critical points that essentially boxes the body. This process has taken the most effort and time. I don't expect to be racing the car but wanted a stronger body for those times that I will be mashing on the pedal. I wonder if anybody here has any input from those that have transplanted an M6 engine into an E9. Though that in stock form won't approach what a turbo charged S52 would produce, what have they done to strengthen the body. Will post pics when done.
 
Wow, at least your are keeping the roundel intact...
Covid should be accelerating restoration projects...just like it is accelerating home remodeling projects all over the US.
Where I see a weird slow down is retail, even baristas brewing espressos seem to operate in slow motion...

Do post pictures! Does DMV make you pass emissions on such a 1972 car?


SoCalE9 said:
Jeff Tighe (Orange County) is currently performing restomod on my 72 CSi. Been at his shop for almost 3 years. Delayed because of covid. Just wanted to ask the forum if anybody else is doing similar restoration/modifications. Jeff is doing the job with the following:

S52 M3 motor with performance tuning from Bullet
High flow cat
Turbocharged with all plumbing and intercooler with dash mounted boost gauge
6 speed transmission
3.43 LSD
Jeff modified the suspension for adjustable shocks (all four corners)
Unibody strengthen/welded (stitched) at critical areas to handle the increased hp and torque
Larger brakes
Dual disk clutch

Change color to MBZ silver from polaris, Jeff had done one that was done with red interior in black (looks really good), but wanted a lighter color
Burnt red interior
Alpina steering wheel
Alpina wheels
European light bulbs
Power windows all around
Custom console to house the 6 speed shifter
New sapele wood trim

Thank you
Click to expand...
 
Last edited:
Arde,

It is pre '75 car, no smog or inspection required even if engine is replaced.
 
Arde,

The cat is required to provide some back pressure for the motor. Direct flow causes it to run too lean that the O2 sensor can't compensate/control for.
 
I should have know that. Somebody had explained to me that unrestricted exhaust is not optimal...

SoCalE9 said:
Arde,

The cat is required to provide some back pressure for the motor. Direct flow causes it to run too lean that the O2 sensor can't compensate/control for.
Click to expand...
 
Arde said:
I should have know that. Somebody had explained to me that unrestricted exhaust is not optimal...
Click to expand...

Apparently @OLD_DTM never got the memo...
DSC09614_2.jpg
 
Call me crazy but a 6-spd in my E46 M3 was hard for me to shift fast without sometimes going into the wrong gear. I much prefer a 5-spd although I don't know if one can be used behind your motor. Doesn't seem like a turbo would need the short gearing but maybe some like to keep in a short power band.
 
pics or didn’t happen :p

jk, sounds like a monster build! are you planning to drive it on the road?
 
SoCalE9 said:
Arde,

The cat is required to provide some back pressure for the motor. Direct flow causes it to run too lean that the O2 sensor can't compensate/control for.
Click to expand...

SoCalE9- If you will pardon my bluntness, that is incorrect. Engines ran for decades with just short pipes just fine. There is also zero correlation between AFR and backpressure in a correctly-tuned system, as the system is still closed. (meaning, having reduced backpressure in the exhaust doesn't bring in additional unmetered air, which would throw off the AFR, it all still has to go through the MAF/AFM/MAP/AlphaN map. Any AFR shortfalls are due to tuning, not the system itself.) Reducing backpressure can modify the residual charge amount, changing the AFR, but again, that is due to a specific tune, not the system.

Eliminating the backpressure on an engine designed for it, however, will cause exhaust valve issues, as the total energy transferred to the exhaust valve during each exhaust stroke increases (due to higher local velocities and higher overall temperatures, as more of the flow exits when the temperature is highest) leading to exhaust valve / valve seat failure. In this instance, however, the turbo itself will provide more than sufficient backpressure, wastegate open or closed. (wastegate open still reduces the exhaust flow diameter, increasing backpressure)

I would argue the cats are nice from an environmental perspective, but they will not make your car run better. It should simplify the integration of the S52 EFI system, though, as the system uses pre/post O2 sensor rationality checks for smog purposes. The system only uses the pre-cat sensor for fuel/timing adjustments. Are you going with a standalone EFI or a modified S52 system?
 
Don't disagree with your statements. Bottom line is that back pressure induced by the cat is required for the S52 to function correctly
 
SoCalE9 said:
Don't disagree with your statements. Bottom line is that back pressure induced by the cat is required for the S52 to function correctly
Click to expand...

It is also illegal to swap in a newer motor without the corresponding emissions system but who’s checking?
 
Considering the new motor minus the cat would likely blow cleaner than a stock medium mileage motor in decent tune. If the S54 brain needs it, then so be it. Going to be a rocket regardless...
 
Ah, but you could mine the palladium out of the converter and fund the entire project that way. You need it for back pressure, not as a catalyst :).

A friend has a Prius parked on the street in front of his SF house, and it has taken less than a week between replacing a stolen catalytic converter and the thieves stealing the brand new one, three times. Redefines turning the other cheek my friend...


SoCalE9 said:
Don't disagree with your statements. Bottom line is that back pressure induced by the cat is required for the S52 to function correctly
Click to expand...
 
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