switching over to SD tomorrow i will give an update once we do it.

 

I dont know, but good idea bringing up the CONS.

Anyone got any CONS to doing SD?

 

I think tuning SD is pretty simple. I had mine dialed in very quickly.

The only reason I am not full time SD right now is because there is either a 'bug' in the present code for certain ROMs or something else is going on. You can read about my issue in the v7t6 thread (the one labeled something like 96530706+SD+DMA+LiveMap working). A few others have posted logs that have shown the same thing, while others have not noticed it.

In a very specific low map and rpm range I was getting a very jittery IPW, causing what felt like mini fuel cuts or misfires.

Aside from that, I would say that there are more advantages to SD than disadvantages at this point.


Eric

 

There was a difference both when I switched to speed density and when I remove the MAF BUT (did you notice the huge but) I had a completely stock tune minus a couple points of fuel around 220-260 load and then I had already done quite a bit of tuning on the car with SD before I paid much attention to when the turbo was spooling and not how hard it hit when it did so YMMV. I suspect that the only boon to spoolup that SD provides on its own without the hardware change is the lean spike that you get if you don't change your accel enrichment tables.

 

I have been working on a buddy's car that is SD patched, and due to the quirkiness of his car is the only reason I have not switched over myself. I have a rom already patched I just need to upload the rom and tune, but I am weary to pull the trigger...

 

Another benefit is not having to worry about the MAF honeycomb getting sucked into the turbo on a higher HP car.

 

The slight lean spike, get your trims perfect and this will be sorted.

 

the_mork was referring to the asynch accel vs tps table. This needs to be adjusted a little bit to adjust for lean conditions on initial throttle input when changing to SD.

 

How much exactly is 'a little bit'?

I only ask as I upped my values quite a lot and I was still seeing very lean conditions.

I have switched back (again) for now until i can figure out what's going on.

Oracle, FYI, i'm using PTE 880s with trims that are very tight.
John Banks mentioned in a post that you upped the asynch vs tps delta stuff quite a lot on a car you tinkered with. Could you let me know what your final values were please?

To the OP,

As already mentioned, I found the main benefit on my setup (esp when it's fully sorted) is the 'smoothness' and lack of lift off bucking.

I would imagine the major con would be deciding which lampshade to fit

 

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On others I have increased them alot more. Depends on car + mods.

 

also, adjust fuel maps, increase fuel in those loads only. Don't worry about having a very lean to rich fuel jumps.

 

Another benefit for the drag racers is the ability to run a forward facing manifold

 

Less pressure drop pre turbo is less back pressure on the turbine which allows it work more efficiently.

As this happens things like EGT induced knock limitations lessen. Lucas and I did a back to back on a pumpgas 3582HTA car and with the car at the limit on the MAF at 26psi it did 482whp. Removing the MAF and running no filter with NO TUNING CHANGES and making a pull within 2 minutes yielded 495whp. The next morning with a 4" filter, the same boost level, and the dyno set to STD correction as it had been the night before I was able to add more timing and get the number to 510.

On a 350whp pumpgas car it seems that it really is woth 10whp, 15whp by 400whp. On a strung out E85 car it is harder to see the initial whp increase, though the torque is noticeable. I think some of it is really related to a fuel that is knock resistant and being able to push the envelope.