Schrick 282 with D-Jet ?

A

Aussiecsi

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Hi guys, I'm about to embark on having the engine rebuilt in my '74 3.0 csi . Nothing too fancy , just a cam & headers envisaged. It would appear nothing too controversial with installing headers but this does not appear to be the case in respect of a 282 cam ?

I've searched some previous threads/posts and there was one back in 2007 by AndyM ( who seemed pretty knowledgeable ) and he advised against it and better to keep stock cam ( if D-Jet is to be retained ) . So, I just thought I would try and find out if anyone is running a Schrick 282 in an otherwise stock D-Jet engine and if any "issues" ?. Interestingly, W&N offer a Schick 282 specifically for injected cars so I would've thought a 282 was "tried and tested" so to speak ...or am I being naïve ?( Albrecht advised anything over this requires Motronic ) .

Comments with first hand experience please !
Cheers, Simon
 
You have a "3" cam now that is a 272 degree.
That Schrick cam is higher lift and longer duration.
Motronic cars don't use manifold pressure sensors and only 3 positions at the TPS
D-Jet uses vacuum and several dozen TPS positions.
Hot cams screw up manifold pressure sensors so you want to avoid them on D-Jet.
Your manifold pressure sensor only has 3 positions- if you want to modify it let me know I can have it re-calibrated.
 
Hrmm,
actually the D-jet TPS has only two positions - idle and off idle. Addtionally it has about 20 trigger areas which cause extra fuel to be injected when moving the right foot and open the throttle up, like a acc pump in a carb. The MAP sensor uses resistance as a linear function of the vacuum in the manifold.

Sfdon: do you recalibrate them on the car when running or in a bench setup?

Cheers
A
 
We use Gus at Pacific Fuel Injection

Pacific Fuel Injection
Gus Pfister
153 Utah Avenue
South San Franscisco, CA 94080

650-588-8880

The stock cam grind creates high vacuum at idle and lower engine speeds, A Schrick cam is the opposite, as it's designed to pull in lots more air volume at higher RPMS, so the fuel map is essentially opposite of what it needs to be. Add high compression pistons and it's even worse!
 
This is an interesting topic - I have a 282 schrick cam and feel that the car is always running too lean high up - so do we need to get the MPS recalibrated? Anyone in Europe done this?
 
Hi Mario,

So if i send it to them and explain I want it remapped for a 282 degree Schrick cam they will do it?

Regards,

Rohan
 
Just a question:

how do you "recalibrate" the MPS to make it work at all rpm with a other-than-stock cam?

The standard problem when putting a tuning cam in a D-jet engine (regardless of which manufacturer) is that it will run rich on low revs and lean up on top revs.

To my knowledge it's only possible to shift the richness of the mixture and when doing so you do it for all rpms. The fuel needed for a specific load at a specific rpm is provided by the ECU and to tweak that you have to start changing those small resistors...

Please correct me if I'm wrong

A
 
Sorry, late to reply . . .

Gus will need to know what you have for running symptoms right now, in our case it was clear, we had very low vacuum at idle and higher vacuum at open throttle . . . as I recall Gus rebuilt and calibrated for this . .

A, I can't tell you what Gus did to the MPS to solve our running issues, I only know it worked perfectly when it all went back together!


Mario
 
Hi Mario,
I called Gus today. He said he does not recalibrate the MPS. He recommended Robert from Livermore Fuel Injection as Don suggested. Robert will do it for 3 bills.


Mario L. said:
Sorry, late to reply . . .

Gus will need to know what you have for running symptoms right now, in our case it was clear, we had very low vacuum at idle and higher vacuum at open throttle . . . as I recall Gus rebuilt and calibrated for this . .

A, I can't tell you what Gus did to the MPS to solve our running issues, I only know it worked perfectly when it all went back together!


Mario
Click to expand...
 
Mario, perhaps he never calibrated them himself but sent them to the shop Don mentioned. Robert at Livermore certainly does do the MPS units. They both are in California.

Mario L. said:
Wow . . . I've only ever used Gus in the past 5-6 years . . please let us know how this works out for you!

Mario
Click to expand...
 
DerSchwede- good answers...thank you.

From edGs post...

"Under the cover is a circuit board with 22 segments, across which three wipers are swept as the throttle butterfly shaft moves. One segment and one wiper make contact and signal the ECU when the throttle is closed. Another segment and wiper make contact to signal wide open throttle. The middle wiper sweeps the remaining 20 segments as the throttle is opened. Each time it "climbs" a segment, it signals the ECU to fire all injectors one additional time. This is, essentially, what D-Jet uses in place of a carburetor's accelerator pump."

This site has some great people!
 
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