Help a newbie with tune after Cam upgrade

[noesfacil]

Hi all

I just replaced the original cam in my 2002 z06 corvette LS6 engine with a custom cam and had the throttle body ported.

Car has LG super pro long tube headers, blueprinted heads and halltech cold air intake. Car was producing around 400hp before cam and throttle body upgrade and was tuned for 104 sunoco fuel.

After starting up perfectly the first couple of times it now has a hard time starting as if it has no fuel (yes, we checked and it has fuel).

Once it starts it maintain the idle but if I rev up it shuts off when coming down in RPM.

Will the ECU reprogram itself and adapt to the new upgrade by driving the car around or will it be necessary to re-tune?

If re-tune is necessary, can anyone give me some tips on where to start in terms of re-tuning the car?

I have some dyno time on wednesday and would like to have an idea where to start.

These are the new cam specs:

232-240 duration
0.598 intake lift
0.600 exhaust lift
112 LSA

Also upgraded to Comp 921 dual springs, spring seats, seals, Ti retainers and pushrods.

Thanks in advance.

NoEsFacil

[eficalibrator]

Hi all

I just replaced the original cam in my 2002 z06 corvette LS6 engine with a custom cam and had the throttle body ported...


...Once it starts it maintain the idle but if I rev up it shuts off when coming down in RPM.

Porting the throttle body changes airflow in relation to blade angle, particularly around idle. What the ECU thinks should be happening no longer matches the reality of your ported TB. The factory intentionally shields part of the flow path at low angles in order to give the ECM better precision in air metering at low flow rates. If you port the TB by removing this hump, you have also changed idle control and return to idle behavior.

Put a stock unported TB back on it. ;)

[The Alchemist]

Hi, changing a camshaft, even a mild cam upgrade like 220/220 at 50thou requires a full retune of the ECU/engine. And by "full" I don't mean a few hours on a dyno either. Almost every table will require some degree of tweaking to obtain a nice drivable result, with some degree of economy, good cold start behaviour and last of all good power on the dyno. I list the dyno LAST as I find I spend 60 to 70% of the retune time "ON ROAD" tuning and about 30 to 40% of the time on the dyno to get a good overall result for the customer.
Thats just me :) but I never get cars coming back with odd querky starting issues hot or cold, auto cruise effects, poor overun, jerkiness in low speed traffic and all those other things that will bite you if you do a half pie job.

As far as "tips" go >
if you haven't tuned engines before I would seek out a good EFILIVE dealer in you locality and go pay them a visit and have a chat paying attention to the above points.....
If you HAVE tuned engines before I would start with a visit to a good dyno operator and get your VE table dialed in, timing dialed in then start on the task of sorting all the little issues that a cammed car brings with it.
Theres plenty of threads on this forum that have excellant pointers on these issues in great detail so no point repeating them all here.

Hope this helps,

Mike

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