General Tuning/Idle Airflow LS2 TVS2300 NW 102 Throttlebody Questions (E40)

[Pabs1]

Just ordered a tvs2300,

writing up a base tune before it gets here...

-In the past I have had issues with 102mm throttle bodies. Addressing it via HPtuners is just a matter of getting the correct ETC scaler value and adjusting the idle airflow table. Is there a write up out there explaining what exactly is the effect of raising the values of this table? I mean I do it all the time with a cammed car its just I don't understand how it works exactly and what are the symptoms of raising the value too much versus reducing it. How would I go about messing with this parameter on my new supercharger and the Nick Williams tb.

-When it comes to part throttle ignition timing; on this particular car, the gto was never intended to be supercharged. Its compression is the highest of all the base LS engines (between LS1,LS2, and LS3). As a result I dont want to push my luck with the boost and will stick with the supplied pulley (6psi) especially since its a high mileage car. GM mapped out the timing tables for its OEM specs. So knowing this, it would be safe to assume that if I don't reduce the low end part throttle timing portions of the table I run a risk of getting some occasional knock.

Assuming that is true I see several ways to go about that...
1st- I can test drive the car and data log my daily driving routines. If I notice knock here and there just reduce the timing in those areas
2nd- Copy the low octane over the high octane table and advance timing across the map till I feel that the car gains no more partial throttle response/power or encounter knock
3rd- Download the stock tune file of a Vauxhall Monaro VXR500 which is technically a British supercharged GTO from the Factory with a MP112. (Have not checked the repository to see if it is available) and work off of that.
4th- Use the stock timing table from a ZL1 Camaro or ZR1 and work off of that

I just feel like option 1 is lazy and just crudely patching up any knock that may arrive. I want to experiment with different styles of going about this.

- I have heard things on the internet about how LT headers bleed off boost or reads as if you lost a psi or two on any gauge. Is this true? Or that 102 throttle bodies help pick up boost by a psi or two. Is it worth going through the trouble of tuning for this Nick Williams 102 on a stock supercharged ls2 or should I switch back too the stock throttlebody

Any advice or clarification on any of the mentioned points is appretiated

[GHuggins]

I know I'm kinda new to tuning, only been doing it for about 9 months, but we did work a little dirrectly with Nick to address some of his TB problems. Most people experiancing problems with his TB's just don't have the bypasses set up correctly in the tune and since the TB is inevitably making more boost, it causes the bypass to open (most go to the 102's right around the same pulley config levels-12 to 14psi setups). Then there's the fact that he based them off of the ls3 platform, which has a lot more play in the gearing than say the positive displacement supercharged ls's do, but there's a way around this. All you need to do is install a TB spacer "102 adapter" from summit and turn the TB over so air flow through it won't "disturb" the blade. Of couse if your using a tvs2300 you will also more than likely need to port the inlet to have any use of the 102tb in the first place. Then of course air and ETC's scaled correctly. Nick does currently have a ZL1 high clearance low profile TB in the works just for supercharged scenarios if you really just wanted to wait.

Timing - if you do go with ZL1's, just keep in mind their much less compression from factory.

Now as for headers, yes you loose about 1 to 2 psi depending on how restricted your exhaust setup originally was. For example after installing longtubes on the zl1, we had to go to the next crank size to get back what we had lost.

Just some thoughts on the subject.

[MikeOD]

In the past I have had issues with 102mm throttle bodies. Addressing it via HPtuners is just a matter of getting the correct ETC scaler value and adjusting the idle airflow table. Is there a write up out there explaining what exactly is the effect of raising the values of this table? I mean I do it all the time with a cammed car its just I don't understand how it works exactly and what are the symptoms of raising the value too much versus reducing it. How would I go about messing with this parameter on my new supercharger and the Nick Williams tb.

The PCM uses the ETC Scalar and the base running airflow table to calculate the throttle plate angle to use to control the idle. If you've got the engine idling nicely with the stock TB, you should be able to just adjust the ETC scalar, and the PCM will still get idle right.

When you modify the engine, you modify that airflow table and essentially you increase the bare minimum allowed airflow. At that point, if the PCM can't close the TB enough to bring idle down, it will have to pull spark advance out (you'll see cars idling with almost no spark advance when tuners do this). The other symptom of adding too much to this table is a "cruise control" feel to the car, where when you're in gear and off the throttle, you'll feel like the car is accelerating anyways...which it is because the table will be pushing the TB open.

Check this out http://www.hptuners.com/forum/showth...103#post136103 ...you can read through the whole thread if you want, but that one post really sends things home nicely...what it tells you to do works well.

[Pabs1]

The PCM uses the ETC Scalar and the base running airflow table to calculate the throttle plate angle to use to control the idle. If you've got the engine idling nicely with the stock TB, you should be able to just adjust the ETC scalar, and the PCM will still get idle right.

When you modify the engine, you modify that airflow table and essentially you increase the bare minimum allowed airflow. At that point, if the PCM can't close the TB enough to bring idle down, it will have to pull spark advance out (you'll see cars idling with almost no spark advance when tuners do this). The other symptom of adding too much to this table is a "cruise control" feel to the car, where when you're in gear and off the throttle, you'll feel like the car is accelerating anyways...which it is because the table will be pushing the TB open.

Check this out http://www.hptuners.com/forum/showth...103#post136103 ...you can read through the whole thread if you want, but that one post really sends things home nicely...what it tells you to do works well.

Can you try posting a link? For some reason I cant find the thread, thanks for the input

[Pabs1]

I know I'm kinda new to tuning, only been doing it for about 9 months, but we did work a little dirrectly with Nick to address some of his TB problems. Most people experiancing problems with his TB's just don't have the bypasses set up correctly in the tune and since the TB is inevitably making more boost, it causes the bypass to open (most go to the 102's right around the same pulley config levels-12 to 14psi setups). Then there's the fact that he based them off of the ls3 platform, which has a lot more play in the gearing than say the positive displacement supercharged ls's do, but there's a way around this. All you need to do is install a TB spacer "102 adapter" from summit and turn the TB over so air flow through it won't "disturb" the blade. Of couse if your using a tvs2300 you will also more than likely need to port the inlet to have any use of the 102tb in the first place. Then of course air and ETC's scaled correctly. Nick does currently have a ZL1 high clearance low profile TB in the works just for supercharged scenarios if you really just wanted to wait.

Timing - if you do go with ZL1's, just keep in mind their much less compression from factory.

Now as for headers, yes you loose about 1 to 2 psi depending on how restricted your exhaust setup originally was. For example after installing longtubes on the zl1, we had to go to the next crank size to get back what we had lost.

Just some thoughts on the subject.

Well now, you brought up something i completely overlooked.

So you are saying in regards to the Nick Williams tb, I am going to have problems with the TVS's internal bypass valve. I lost you after that. If I am not mistaken; the newer pcms (E67) do have a tab for supercharger parameters and functions. The E40 (2006 GTO) does not have this available. Is that what you meant by "Most people experiancing problems with his TB's just don't have the bypasses set up correctly in the tune..."?

Can you elaborate on the whole inverting the throttle body point? There I lost you completely...

[MikeOD]

Can you try posting a link? For some reason I cant find the thread, thanks for the input

I did post a link...where it says "Check this out"...the text after that is a link.

[GHuggins]

Well now, you brought up something i completely overlooked.

So you are saying in regards to the Nick Williams tb, I am going to have problems with the TVS's internal bypass valve. I lost you after that. If I am not mistaken; the newer pcms (E67) do have a tab for supercharger parameters and functions. The E40 (2006 GTO) does not have this available. Is that what you meant by "Most people experiancing problems with his TB's just don't have the bypasses set up correctly in the tune..."?

Can you elaborate on the whole inverting the throttle body point? There I lost you completely...

What I was referring to were people with stock from factory blower setups. Most of these people are going to the 102TB's right around the same boost levels (12 to 14ish) and with the the 102's allowing more boost to be made (ie-flowing more air into the superchargers) they are then hitting their boost limits of the programming causing what I and others often refer to as a throttle "slap shut" scenario. You can youtube NW102 fail and see what I'm talking about on a ZL1 where yet someone else is blaming the 102TB for their problem. Basically it starts typically in 3rd gear as being noticed and its like you have no throttle control with the engine bucking. This is just the bypass constantly opening and closing.

As for turning the TB over. Well, probably shouldn't even be saying this, but most stock applications such as the ZL1's and LS9's have a hump in the inlet of the supercharger for clearance to the waterpump. This won't cause any problems with the stock smaller diameter throttle plate, but when you get the longer throttle plate of the 102 into the equation, the throttle plate will go into this "air disturbance" area resulting in high and low pressure zones caused by high and low speed airflows being caused by the throttle plate now deviding up this part of the supercharger inlet. If installing the throttle body in it's traditional orientation with motor and hookup on the driver's side of the engine, this high and low air pressure will work against the throttle plate trying to force it to close. SO now you have airflow trying to close or working against the throttle plate, then you throw into the equation an already sloppy gearing (remember before when I mentioned the ls3's tb being used as the "blue print" to make the 102), then what you have is a very uncontrolable throttle blade or atleast one "free dancing" in the intake stream. What was done to cure this, was to use a holley 102tb spacer to get the plate out of the disturbance area and then flip the TB over (motor and plug-in on passenger side of engine). We actually also discovered we make even more boost sooner on by doing this as well. (notice my signature-those power levels are with no internal engine mods and running 14lbs boost pulley config with no knock retard)

If your using a gm 2300 then your going to have to plug off your boost bypass portion of the sc bypass. This is all that's necessary to bypass the blow off valve.

[Pabs1]

Something else just occurred to me. Will my stock fuel pump provide enough fuel to meet the demands at WOT. I am considering upgrading to an inexpensive pump like maybe lingenfelters to be on the safe side.

If its neccesary, do i have to touch up on any tables via HPtuners like with the injectors to have the pump operate properly?