Engine displacement

Guero

Active Member
Oct 11, 2005
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I got a tune from a buddy, with a 331 or something like that, and on his tune hes got 1872.15 as his engine displacement. And when i open up the CBAZA file it has 2436.72 as the engine displacement. Is there a calculation to get the C.I.:shrug:
 
HOLY crap!!! what is he running a p51 mustang engine:eek: .

I would look at a stock file and copy the factory CID...unless your running a 306. For a 306 its 306.133.

Mybe he is running boost or something and needs the extra CID for load...but I think it would be better to do that in the sea_level_load area? but then again I dont run boost or have any exp. with it.

Its little reasons like that why its best you make your own base tune.
 
yup, don't forget to change ur injector values to 30 for hi-slope and around 34 or so for low slope. You would also prolly have to change the breakpoint and minimum pulsewidths....Not sure what those values should be on 30 pounders
 
a good starting point would be 30 and then 30 x 1.2. so that would be 30 and 36 for slopes.

Also what base are you using the gt or the cobra file? Reason being that if you use the cobra file make sure the breakpoint for starters is the t4m0 if you use the diff. slope numbers (and you will since you have 30's).
 
CBAZA is like the dad of T4MO (GT) and the J4J1 (Cobra)

U can search on the tweecer forums for either a base Cobra (J4J1) or a base GT (T4MO) file...both of these files are still under CBAZA.

The only difference is that one is calibrated differently than the other..the cobra has different fuel tables, spark tables, etc. than the GT has.

Most people like to take a base cobra tune (again, J4J1) and use that to do their tweecing. The cobra tune dumps more fuel and has less spark than the GT tune does, IIRC...this is why a lot of the GTs like to ping...they come lean from the factory.

So in short...Under the CBAZA family you can have either the J4J1 or the T4MO base tune and then build from either one. There's another tune (ZAO) but thats for the Cobra R.
 
Guero said:
I saw the AFR on the Tweecer wa 14.67 i think, so if i lower it would i be richer?

You want to add fuel via the fuel tables. Messing with scalars is a cheap and dirty way to tune... the "correct" way is to hit those tables. It's more of a pain but if you just tune via scalar you might as well twist the dizzy or add an AFPR.

Adam
 
since we are on the topic of tables

spark controle

to gain controle of the spark curve, you want to for the most part mess with the top 2-3 row's (across) in the base timing alt timing table. This will be your WOT spark. No more need to have high timing in areas you dont really need it.

there are 2 ways to gain controle of the spark tables on our eecs from what I have seen others do.

1. set the MBT table, Altitude table, and borderline table to 55 in all cells, then use the base table as your timing settings.

2. set the MBT table, borderline table to 55's in all cells but make the top 2-3 row's (across) in the base and alt. tables match.

log after setting your timing to what you want (rec. to start low and slowly go up) and check the load and timing to see if at that load your getting what timing you were commanding.

Another tip is to N/A have all your timing in (at full advance, or have your highest timing setting) around 2,500rpm. so 1500rpm you have 16*, then 2000rpm you have 18* then 2500rpm you have 30* as an example.

Now for fuel the same kinda aplies that you want to really only mess with the WOT areas (check with a W/B to make sure at this point and take out timing when messing with fuel to be safe). Us 94-95-ers use the Base_fuel_OL. If your maf is correct and your injectors are also setup correctly you should see the WB matching your commanded.