Classic Retrofit CDi+ box

[Carbster09]

Guys, I have the car at the shop getting some work done, engine out service and dyno. Does anyone have any experience with Classic Retro's improved CDi box? My original box failed a few years ago and I had it rebuilt, it works fine, but if Classic's box yields any decent gains I would go this route. My car is running a K27 w upgraded full width IC and a few mods. According to their website they got an extra 10ft-lbs in the mid-range on a 2.4 NA car. I just don't believe I will see as much on a boosted 930? Ideas/Opinions? Chris

[356911930]

IIRC...

If they have finished developing their boost retard component you can then control your idle and ramp up rpm settings which would add throttle response. I believe you can also do this with the MSD box (Programable) and boost retard.

Rahl

[jlj]

I have it in my 1982 turbo. Amazing upgrade . highly reccomended

[356911930]

jlj,

Do you have the Classic Retro CD box and boost retard? Or do you have the MSD box with boost retard? What improvements have you seen?

Thanks,

Rahl

[jlj]

Originally Posted by 356911930

jlj,

Do you have the Classic Retro CD box and boost retard? Or do you have the MSD box with boost retard? What improvements have you seen?

Thanks,

Rahl

The box is plug and play and doesn’t need anything else. It is essentially dual spark and has consistent spark from idle to redline. The car runs smoother thru the whole rev range , no flat spots. Pulls hard. Everyone who has driven it marvels at how well it idles and pulls to redline. Only other mods are , k27, fabspeed airbox and rarlyl8 exhaust

[jlj]

https://m.youtube.com/watch?v=AHPTee7ZVm0

[jlj]

Bosch CDI box vs Classic Retrofit CDI+ - Classic Retrofit

[356911930]

It looks like Classic Retrofit has never completed the boost retard project. To get the most out of a CD box replacement you must have the boost retard to control spark timing as boost comes on. Tis way you can run more advance through the RPM range up to boost coming on when the MSD unit will then start to pull out timing. For this reason I would go with the MSD unit with boost retard function. I believe this is accomplished with a MAP (Manifold Absolute Pressure) sensor.

Rahl

[dos531]

Originally Posted by 356911930

It looks like Classic Retrofit has never completed the boost retard project. To get the most out of a CD box replacement you must have the boost retard to control spark timing as boost comes on. Tis way you can run more advance through the RPM range up to boost coming on when the MSD unit will then start to pull out timing. For this reason I would go with the MSD unit with boost retard function. I believe this is accomplished with a MAP (Manifold Absolute Pressure) sensor.

Rahl

Agreed. Without boost retard you're leaving a lot on the table. Even the factory vacuum pot setup reduces timing under boost. I would never put an ignition on a 930 without some form of boost retard. Any system without it is a downgrade.

[Neil Harvey]

I think a lot of emphasis is placed upon boost retard in these early engines. The vacuum control certainly works, but the retard function is very slow compared to the onset of detonation.

The Classic CDI is a CDI unit that can be used with the factory timing curve set in place. It comes as factory CDI replacement still leaving the vacuum retard system in place.

However, the classic unit has the ability to recurve the ignition timing curve with the distributor locked out. Have not done this, but I cannot see why the timing curve cannot be retarded as the boost comes on as you would with any EFI system.

Whatever your max manifold pressure is, or more accurately stated, your max cylinder pressure, would be the max timing advance you could run. The timing curve would follow the cylinder pressure.

More advance at the lower RPM's and as the boost increases the timing curve would be retarded some and as the RPM increases in the higher RPM's and as the cylinder pressure drops you could add in more advance. I would think you would program a curve 2° away from knock to be safe.

Really no difference between doing this with a fixed timing curve to suit each engine or allowing the unit to retard as programmed.

Any other way requires knock control in an EFI system and even then you, the tuner has to set the noise threshold by deciding what is noise and what is detonation.

Another really important factor to consider is the quality of the CDI itself. We would never use an MSD product on any of our engines due to their manufacturing quality. Having looked inside both, the Classic unit is heads and shoulders above anything MDS sells.

Choose wisely and understand what you are actually buying in the way of features. Maybe its no better than a well tuned ignition curve.

[RarlyL8]

Another really important factor to consider is the quality of the CDI itself. We would never use an MSD product on any of our engines due to their manufacturing quality. Having looked inside both, the Classic unit is heads and shoulders above anything MDS sells.

You just answered my question. I looked at the Classic video and note that the timing stays steady, does MSD remain steady as well? If not you haven't gained much, if there are quality issues you are worse off.

[Carbster09]

I agree, as I know of MSD's quality issues. Good feedback, and I have a Classic CDi on the way. I have access to a dyno, so the "plan" is to do some testing before and after installation! My car is similar to jlj's w a K27 and my fantastic sounding RarlyL8 exhaust. Oh and I have a 964 intercooler stuffed in the back as well!

[Edelweiss]

Well said !

Originally Posted by Neil Harvey

I think a lot of emphasis is placed upon boost retard in these early engines. The vacuum control certainly works, but the retard function is very slow compared to the onset of detonation.

The Classic CDI is a CDI unit that can be used with the factory timing curve set in place. It comes as factory CDI replacement still leaving the vacuum retard system in place.

However, the classic unit has the ability to recurve the ignition timing curve with the distributor locked out. Have not done this, but I cannot see why the timing curve cannot be retarded as the boost comes on as you would with any EFI system.

Whatever your max manifold pressure is, or more accurately stated, your max cylinder pressure, would be the max timing advance you could run. The timing curve would follow the cylinder pressure.

More advance at the lower RPM's and as the boost increases the timing curve would be retarded some and as the RPM increases in the higher RPM's and as the cylinder pressure drops you could add in more advance. I would think you would program a curve 2° away from knock to be safe.

Really no difference between doing this with a fixed timing curve to suit each engine or allowing the unit to retard as programmed.

Any other way requires knock control in an EFI system and even then you, the tuner has to set the noise threshold by deciding what is noise and what is detonation.

Another really important factor to consider is the quality of the CDI itself. We would never use an MSD product on any of our engines due to their manufacturing quality. Having looked inside both, the Classic unit is heads and shoulders above anything MDS sells.

Choose wisely and understand what you are actually buying in the way of features. Maybe its no better than a well tuned ignition curve.

[Jonny H]

We have around 30 Turbo cars running CDI+ units. Almost all of them are using the distributor weights to control timing and retain the standard vacuum advance and retard. These are physically separate mechanisms to the 'main' curve provided by the weights.

Reports generally come back of better idling, pickup and 'driveability' making driving the car less 'binary' in terms of power delivery. Given the healthy power output of even a standard turbo, it is hard to quantify the exact power gain at peak power, if at all until we get one on the dyno. This all without mapping so any change is down to the dual spark output.

Loren Beggs at 911Design in LA did, however, make changes to the ignition map in a Gemballa Turbo and got the engine to come on boost a little sooner. I don't have the exact details but I'm sure he'd be willing to discuss.

[356911930]

I see there are several well respected voices on this thread in favor of the Classic CDI. I had my brother buy on for his NA and it works well.

But...

"However, the classic unit has the ability to recurve the ignition timing curve with the distributor locked out. Have not done this, but I cannot see why the timing curve cannot be retarded as the boost comes on as you would with any EFI system. "

This is not possible with the Classic unit, sorry.

Jonny can reply here about the Classic CDI not having any retard for the turbo engine except what is provided by the stock distributor...but the MSD CD box does, at least from what I have read.

Interested to hear more,

Rahl

[Jonny H]

Hi Rahl,

I think there are two questions running in parallel here to do with boost retard and CDI+

Q1) Does the unit work with the factory boost retard?

A) Yes, since it is built into the distributor. You can change the main timing map using CDI+ and not effect the retarding function.

Q2) Does the unit have an independent boost retard capability?

A) No, not currently. If there was enough interest we would consider adding it.


Can you help me understand why the factory boost retard system is not sufficient? Are you trying to provide a custom map of retard against pressure?

[356911930]

Hi Jonny,

Yes, you can use timing to ramp up earlier and higher than stock then pull it all back at boost onset to factory setting of 26* or slightly more.

Rahl

[Jajohnsen]

I would also like to see boost retard capability for the CDI+. Would buy one on the spot if it had.

Is the current CDI+ uppgradable to a maybe future boost retard capability, that would be nice and i might get one this year.

For me is the possibility to lock the dist, and change retard amount, and not being dependant on the factory advance\retard mechanism.

[1979-930]

Classic Retrofit is not going to develop it.

Parts.Klassik has been working on one for a couple years and it's not available either. I must be a lot more difficult than it sounds to program in a boost retard function.
The amount of development time and cost for, lets say, 50 to 100 sales total; I wouldn't do it either.

Right now the only programmable with boost retard is MSD.

[Jonny H]

Originally Posted by 1979-930

Classic Retrofit is not going to develop it.

Parts.Klassik has been working on one for a couple years and it's not available either. I must be a lot more difficult than it sounds to program in a boost retard function.
The amount of development time and cost for, lets say, 50 to 100 sales total; I wouldn't do it either.

Right now the only programmable with boost retard is MSD.

It’s not that difficult but you have to consider the amount of development and test time required for a very small market. I still don’t quite understand what the exact requirement is and why the factory system isn’t good enough.