GT350 Intake Dyno..ENJOY!

[Gibbo205]

I lowered mine about 10* F. Fuel base cold can be leaned out to 1.00 lambda sooner vs ECT which might help as well. Cold cam angles also seem to cause odd cold driving behavior.

I've got HP tuners, what cable do I need to connect my laptop to my car? When I get this cable can I just pull the Lund tune from the car and open it and try adjusting some settings or do Lund encrypt their tunes?

Looking at a stock GT and 350 map I can see:
CL 02 sensor temp: 65.56c (Lower this to 55c)

Fuel base cold, could you screenshot your settings or what you would recommend please buddy?

Sponsored

 

[dev1360]

You won't be able to make changes to Lund's tune. And my throttle has always felt the same. These cars are known to surge when cold. That's what we (I) are referencing.

 

[markmurfie]

kinda nice to see a dyno of the difference between VCT non OP and OP enabled and tuned. As terminator2 said the part throttle stuff is so tied in to the IMRC it makes it time consuming to find improvements, but I'm sure the GT350 IM and TB there's going to be great part throttle improvements. Add in the cold engine tuning I can see why this thread is a year old and improvements are still being made. keep at it guys!

 

[Terminator2]

kinda nice to see a dyno of the difference between VCT non OP and OP enabled and tuned. As terminator2 said the part throttle stuff is so tied in to the IMRC it makes it time consuming to find improvements, but I'm sure the GT350 IM and TB there's going to be great part throttle improvements. Add in the cold engine tuning I can see why this thread is a year old and improvements are still being made. keep at it guys!

I'll be working on it a lot more once I get my manifold and throttle body on the car. I haven't bothered finalizing my entire tune because I'm not planning on keeping the stock manifold and throttle body on the car much longer.

 

[Dominant1]

When you guys talk about cold surge are you talking about starting the car up in the morning and taking off without a warm up? I always let my car warm up till the cold idle drops rpm's takes about 4-5 minutes depending how cold it is outside. I know i have an auto so that is probably why i have zero surge but I think letting car warm up for 5 minutes before you take off might help you manual guys!

 

[Terminator2]

When you guys talk about cold surge are you talking about starting the car up in the morning and taking off without a warm up? I always let my car warm up till the cold idle drops rpm's takes about 4-5 minutes depending how cold it is outside. I know i have an auto so that is probably why i have zero surge but I think letting car warm up for 5 minutes before you take off might help you manual guys!

Yes and I'm willing to bet that the auto masks most of the feeling because of the converter and just putting the pedal in one spot and letting the auto shift through the gears.

 

[sandeale]

Ive found that a majority of the surge is produced from the imrc open and closing loads as well as the normal (non OP) VCT mapped points....also taking the time to correct predicted throttle errors (pretty much what is written into the tune telling the ecu to expect x amount of flow at a given throttle position) if the actual throttle angle differs greatly from the predicted throttle angle (all based on airflow) then this can contribute to the surge as well....

Correcting the throttle angle takes multiple datalogs but the end result is worth the effort

 

[WhiteyDog]

When you guys talk about cold surge are you talking about starting the car up in the morning and taking off without a warm up? I always let my car warm up till the cold idle drops rpm's takes about 4-5 minutes depending how cold it is outside. I know i have an auto so that is probably why i have zero surge but I think letting car warm up for 5 minutes before you take off might help you manual guys!

I do the same with mine. I let it warm up until the cold idle drops (first start of the day it's pretty high), and never had any surging afterward. Even if I didn't quite let it run long enough to "warmed up" idle, I still never had any surging. That's why I'm so hesitant to get the 350 TB because it runs so well, maybe I should just leave well enough alone.

 

[09jsw]

When you guys talk about cold surge are you talking about starting the car up in the morning and taking off without a warm up? I always let my car warm up till the cold idle drops rpm's takes about 4-5 minutes depending how cold it is outside. I know i have an auto so that is probably why i have zero surge but I think letting car warm up for 5 minutes before you take off might help you manual guys!

The cold surge issues are generally there until the oil temp comes fully up along with coolant temp. Sometimes it takes 20+ min for it to stop the surge.
I'm really wanting an auto now lol.

 

[EricSMG]

The cold surge issues are generally there until the oil temp comes fully up along with coolant temp. Sometimes it takes 20+ min for it to stop the surge.
I'm really wanting an auto now lol.

Exactly. It has nothing to do with cold start.

 

[Gibbo205]

Exactly. It has nothing to do with cold start.

Its the period of time when the car is in open loop mode which is around 5-10 minutes.

If I leave the car to idle for 2-3 minutes on the driveway to the point the revs drop to under 1000 it drives a bit better.

As soon as oil temp reaches normal on gauge (just enters the green) the car then drives absolutely fine and I believe this is the point where the car enters closed loop because at this point your oil is not at optimal temperature.

At this point my car drives smooth and fine, as it further warms up beyond this point it does improve on but mainly from an engine braking perspective.

I am going to ask Lund what they think about setting the car to enter close loop 10-15c earlier as if I can get it to a point where I can let it idle for a couple of minutes and then a couple of minutes later driving its better would be a great improvement.

Its a daily so it gets driven from cold twice a day and well its quite annoying, I could just give up and refit the stock TB but its obvious from others here that this can be resolved so I shall just keep pushing Lund.

 

[Terminator2]

Its the period of time when the car is in open loop mode which is around 5-10 minutes.

If I leave the car to idle for 2-3 minutes on the driveway to the point the revs drop to under 1000 it drives a bit better.

As soon as oil temp reaches normal on gauge (just enters the green) the car then drives absolutely fine and I believe this is the point where the car enters closed loop because at this point your oil is not at optimal temperature.

At this point my car drives smooth and fine, as it further warms up beyond this point it does improve on but mainly from an engine braking perspective.

I am going to ask Lund what they think about setting the car to enter close loop 10-15c earlier as if I can get it to a point where I can let it idle for a couple of minutes and then a couple of minutes later driving its better would be a great improvement.

Its a daily so it gets driven from cold twice a day and well its quite annoying, I could just give up and refit the stock TB but its obvious from others here that this can be resolved so I shall just keep pushing Lund.

Closed loop usually happens within 30 seconds because O2s get to 160* almost instantly.

 

[Gibbo205]

Closed loop happens within 30 seconds because O2s get to 160* almost instantly.

Ah OK so enabling close loop sooner then would do not much at all. The car drives touchy until oil temp reads normal.

So does something else change on the cars running, just looking for ways to improve the cold start touchiness.

 

[Terminator2]

Ah OK so enabling close loop sooner then would do not much at all. The car drives touchy until oil temp reads normal.

So does something else change on the cars running, just looking for ways to improve the cold start touchiness.

Your cam angles and IMRCs likely need tweaking there is only so my DBW adjustment will help.
I'm about to slap the GT350 throttle body on my stock manifold for now. I'll see how bad it is as is with just the GT350 throttle body settings and I'll adjust as needed until it is to my liking that's the best part about being self tuned.

 

[Gibbo205]

Your cam angles and IMRCs likely need tweaking there is only so my DBW adjustment will help.
I'm about to slap the GT350 throttle body on my stock manifold for now. I'll see how bad it is as is with just the GT350 throttle body settings and I'll adjust as needed until it is to my liking that's the best part about being self tuned.

Can you share what it takes to fix it please in detail when you do it so I can try to pass onto Lund to fix as they do not seem so interested in fixing the cold start aspect of driving, which is bit annoying. :(

Sponsored