Camshaft recommendations for CSi engine rebuild?

[Dan Mooney]

Hi all,

I am about to rebuild my CSi engine and plan on some mild upgrades. Some port work, forged pistons, possibly larger intake valves, etc. Can anyone recommend a good camshaft for use with the stock D jet fuel injection system? I have heard people speak in glowing terms about Schrick cams. Would that be a good option for my CSi?

Many thanks!
Dan

 

[rsporsche]

my guess is the same as the CS (just wouldn't use the mechanical fuel pump lobe) ... but, that being said ... somebody like SFDon should weigh in on what a cam would do to the workability of the D-jet injection. what say you Don?

 

[sfdon]

I think it’s problematic at best.
Timing, fuel, idle mixture, MAP, WOT, AFR, TPS and vacuum will all be wrong.
Call me if you want to discuss.

 

[Dan Mooney]

I think it’s problematic at best.
Timing, fuel, idle mixture, MAP, WOT, AFR, TPS and vacuum will all be wrong.
Call me if you want to discuss.

Thank you Don. PM sent.

 

[teahead]

With all those mods...Megasquirt or similar.

 

[sfdon]

For the record- d-jet mps units get set at 18, 12 and 0 inches of vacuum.
Changing the cam changes the vacuum.
Increasing the advance raises the vacuum but screws up the WOT timing.
With a cam and custom pistons you will put out 240 hp and be 20% too lean at WOT. Adjusting fuel pressure or changing the pulse width will fix the AFR at WOT but super rich at idle.
This isn’t simple math it is more like a very expensive can of worms.
Keep it stock or box the csi goodies up and put in MS...

 

[teahead]

Don, can a Montronic 1.3 (B35 of course) deal w/those changes?

 

[Dan Mooney]

Extremely informative chat with @sfdon. Leaning now towards staying closer to stock with my CSi engine and fuel injection.

Thanks for taking the time today Don!
Dan

 

[Dan Mooney]

I put my super light CSi (no windows, interior) on the Dyno this afternoon. A quick Wiki search pulled up 197 HP and 201 ft/bs of torque for the CSi when new. Using a 15% power drain formula from the flywheel to the rear wheels on the Dyno, that would equate to 167 HP and 171 ft/lbs of torque at the back wheels. We actually saw 150 HP and 163 ft/lbs of torque at the back wheels, which I think are pretty healthy readings. My Dyno driver lifted at 5200 rpm, so there may have been a few more HP to be had.

 

[sfdon]

Don, can a Montronic 1.3 (B35 of course) deal w/those changes?

Barely.
Wrong timing and wrong AFR and wrong VE Table and wrong injectors for 240 hp.
With stock pistons it’s much better.