Help with tuning a 408-where do I start?
08-12-2005, 10:30 AM
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Help with tuning a 408-where do I start? Hy guys, just put together a 408, AFR 225 heads, 244/248 114 cam, Fast 90/90 for a 99 f-body A4. We have already done some preliminary dyno's and it has made 490 rhwp with a safe 12.5 AFR. However wot is one thing and driving it is another. It won't start without peddling the throttle, dumps out tonnes of smoke at start up and burns your eyes when it is running. Everything seems out of wack. I have tuned a bunch of 346 with big cams but never a stroker-where do I start? I'm using HP tuners. Any help would greatly appreciated. Thanks!
08-12-2005, 11:05 AM
#2
what kinda compression you running? i have no definate answers on what to change but here is a list of what would need some work done for sure, im sure you know about them anyway but here is waht i have found
timing you will want to play with some, bigger cubes and different compression will make it different from most you have tuned (found this out by helping a member tune their 383) i honestly would make no changes until you play with the timing in vcm controls and just see where a good starting point for the timing would be.
you may need to take out some more fuel in the ve table as well. look in the olfa table and also lean it out in the higher map cells for cold start up.
depending on the rpm setting you want to make sure you dont have too much air or not enough air getting in the engine. with a 90/90 set up the effective area will have to be modified as well.
these are the main thing to just get the car to run without any gas. mostly trial and error since you dont know where to start at realyl
timing you will want to play with some, bigger cubes and different compression will make it different from most you have tuned (found this out by helping a member tune their 383) i honestly would make no changes until you play with the timing in vcm controls and just see where a good starting point for the timing would be.
you may need to take out some more fuel in the ve table as well. look in the olfa table and also lean it out in the higher map cells for cold start up.
depending on the rpm setting you want to make sure you dont have too much air or not enough air getting in the engine. with a 90/90 set up the effective area will have to be modified as well.
these are the main thing to just get the car to run without any gas. mostly trial and error since you dont know where to start at realyl
08-12-2005, 11:32 AM
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Thanks for the tips. What is the olfa table? On a 346 usually we add to the running airflow and IAC tables-do we do the same on a fast 90 setup or do we reduce the #'s? About the VE table, does the same apply up to 1200 rpm, reducing by like 60, 70 and 80 or do we need to take out more? What kind of IAC vlaues should I be looking for-Most of the cars i have worked with have been C5's. Oh the heads have been milled .020 (AFR 225's) and the compression is right around 10.9 to 1. I have an LM-1 also-will that be any help with HP to get it to run and idle properly? Thanks!
08-12-2005, 01:25 PM
#4
open loop fuel air, its in the close/open loop tab on the left top. you want to add to the airflow numbers for a 90 mm setup as well. iac values should be 30-50 steps. i would start the tune in open loop and use the wideband to fix the spots in the ve table that may be all wacky, the o2s will not be too accurate if they get saturated. let me know if you have any mor equestions and ill try to help
08-12-2005, 03:40 PM
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I have a 408, 90/90 setup, 12.5: CR, 244/248 cam, 52# injectors. Car starts right up and idles like a dream. I am still in the tuning process and trying to eliminate the low speed surging. PM me your email address and I can send you a .bin file for HP Tuners to compare to.
08-12-2005, 03:48 PM
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Originally Posted by 2001 Pewter WS6
I have a 408, 90/90 setup, 12.5: CR, 244/248 cam, 52# injectors. Car starts right up and idles like a dream. I am still in the tuning process and trying to eliminate the low speed surging. PM me your email address and I can send you a .bin file for HP Tuners to compare to.
