TURBO LAG.....

[Roysviper]

What is the best way to launch from a dead stop at the dragstrip, a Twin Turbo Viper?? Especially at a 1/8th mi Dragstrip, when you pull up to the tree, how do you deal with Turbo Lag? As you know in a 1/8th mi race the race is pretty much determined within the first 60'. There is no time to make up for mistakes so the first 60' pretty much will tell you alot when you look at the timeslip. Thanks for any advice on this subject.

 

[uvbnbit]

Enthusiast? Is that another title for someone that has owned about 10 Vipers?

Roy, I think it's gonna depend on the tires quite a bit. I assume you're running DR's? and how well is the drivetrain beefed up?

 

[britospeed]

What size turbos? What engine managment? There are many options depending on your configuration.

 

[Tiago]

you will need some kind of "anti-lag" technology on your engine management, AEM has it. Once it is setup properly, you can have full boost before ever releasing the clutch... hope you have good tires

 

[Roysviper]

Enthusiast? Is that another title for someone that has owned about 10 Vipers?

Roy, I think it's gonna depend on the tires quite a bit. I assume you're running DR's? and how well is the drivetrain beefed up?

I have M/T Street Slicks, Unitrex Half Shafts and axle straps, AEM with 2 Tunes in it from HEFFNERS, low boost and high boost, launch at 5000 rpm and not a drop of wheel spin with 60' of 1.58. After about 10-20 feet out pull like a freight train thru the entire pass running 108 mph at 6.75 e.t., perfectly straight and excellent handling with 12-14 lbs of air in rear tires and 45 lbs in front skinnies and have only made a pass on low boost. The turbo lag is costing me several 10s and I never had that with ROE superchargers so I don't know how to solve it maybe then getting HEFFNERs to do something with the AEM??? Is there something I can do in my driving to compensate? I went to Heffners a few months ago with no appointment and Jason was nice enough to put it on the DYNO put didn't have time to do a tune without an appointment. We drove to Disney for a few days a drove home just purring. With old tune and old plugs and very dirty K&Ns and that long drive (over 1400 mi) it dynoed 739.19 rwhp and 723.97 rwtq on 93 pump gas and low boost, just 1 pull on Dyno. His Dyno man showed me in their computer an old Dyno on my car with fresh tune it dynoed over 800 rwhp on 93 octane low boost pull. Do you think a line lock would make any diference on the launch rather then footbrake with the Turbo Lag??? Thanks for all the input so far with the help....

 

[Roysviper]

What size turbos? What engine managment? There are many options depending on your configuration.

MY Turbos are Garrett GT35Rs done by HEFFNERS and they put in AEM management.

 

[jrod_okc]

So take it it is a auto car? Foot brake and Line Lock? Try changing the converter

 

[Russ M]

It all depends on the turbo's you use, on my car there is no lag but I sized the turbo's to make sure there would be none. Big turbo's are great dyno queens and can be great for straight line stuff of any sort, however if you want a car that has no lag and feels and drives like a normal viper on crack then you need to size your hot side to get on boost at full throttle.

 

[Roysviper]

So take it it is a auto car? Foot brake and Line Lock? Try changing the converter

Its a 6 speed. (I get trans brakes and line locks mixed up,)

 

[99 R/T 10]

Hey Roy, I hope you get this figured out by the 13th of May..............................

 

[1fast400]

Impressive 60' times.

 

[Toma]

Need more info!

Assuming it is a stick car?
Why are you launching at 5000 rpm?
Is this the two step limiter on the AEM? (ie, your foot is planted and it holds it at 5000 for launch)?
Are you at all familiar with the AEM? Can you open the software, pull the tune, retrieve the internal log?
How much boost do you see when at 5000 jsut before you dump the clutch?

If you need, I can look at your tune and make adjustments if you are not comfortable doing it, and email it back.

Does yours have the integrated wideband?

 

[Roysviper]

Need more info!

Assuming it is a stick car?
Why are you launching at 5000 rpm?
Is this the two step limiter on the AEM? (ie, your foot is planted and it holds it at 5000 for launch)?
Are you at all familiar with the AEM? Can you open the software, pull the tune, retrieve the internal log?
How much boost do you see when at 5000 jsut before you dump the clutch?

If you need, I can look at your tune and make adjustments if you are not comfortable doing it, and email it back.

Does yours have the integrated wideband?

I have launched at all different rpms and the higher I bring up the rpm at launch, the faster I run and the better my 60' times. No I don't know anything about the AEM, other then I sent it off to California to the company and they checked it out and upgraded a ground mod and said it is in fine condition and that they did not mess with the tunes that Jason put in it.I see 8 lbs of boost .I don't know how to pull the tune and retrieve anything but at Heffners shop a few months ago they did look at it on their computer and said it was fine but we didn't talk about Turbo Lag because I never raced it yet and was unfimiliar with Turbo Lag to ask about it. My son tunes his Racecar with a computer. Is this something he can do for me? Does he have to have anything special to do it other then the cable? His Racecar is a Pro Mod and he runs in the 4s in 1/8th mi so he knows what he is doing. I have never talked to him about it. Thanks everyone for all this help and input. It is all greatly appreciated.......

 

[Roysviper]

Hey Roy, I hope you get this figured out by the 13th of May..............................

Mike.......I will have no excuses.......I will have fun regardless.....Bring the Turbo Viper!!! Remember this is at HOLT Florida, Not Panama City.....We have a Pro Mod there running 3.50-3.60s at our track... Joey Martins 55 Chevy LOW MAD....Our track hooks great.....

 

[mbccenter]

You can download the program from the AEM website

 

[Roysviper]

You can download the program from the AEM website

I will see if my Son knows how and will the launch with the Turbos be able to be adjusted that way or does Heffners have to go into their tune in the AEM to adjust that. Will messing with it from AEMs end will it mess up or afect the Heffner tunes input? I know these are stupid questions but I no nothing about any of this subject. Thanks for bearing with me and my ignorance.

 

[Toma]

Yup, anyone with a bit of computer knowledge can do this.

You will need an older laptop with a serial port. You CAN try and use a newer laptop with one of those USB to Serial converter, but they are a royal pain. I would borrow an old XP laptop or even desktop if you can get it close enough.

The software is here, you need AEM PRO 1.19. AEM Performance Electronics - All Software & Firmware Downloads

What the 2 step function will allow you to do is set the limiter when the car is not moving to something like 5000 rpm. Then, when you light the stage bulbs, you can plant your foot right to the floor.... you will build more boost since you will set the limiter to cut spark, not fuel and the car will build more boost than part throttle.... you can also add more fuel or reduce timing to get more heat into the exhaust and make even more boost, BUT start with just the normal settings as "anti lag" or "boost builder" can put a lot of heat in your exhaust valves.

**** MAKE SURE**** First time you hook up to AEM, turn ignition on, and SAVE the file that it reads. Then back it up, then back it up again somewhere where you know you won't accidentally touch it, lose it, **** it up lol.

Once you have the AEM software open, turn the key on and it will ask you if you wanna connect to the ECU, click "yes". THen right away, soon as its done its thing, gon under "file" and "save as"

To play with the 2 step, go under "Setup" -> Rev Limiters -? 2 step -> options. Put the fuel cut a couple hundred rpm above the ignition cut.

AEM also has a tech/help desk, so once your son is in front of the software, they can guide him through anything he needs.

 

[Toma]

Also.... do you have a separate boost controller, or is AEM controlling the boost control solenoid?

 

[Roysviper]

Also.... do you have a separate boost controller, or is AEM controlling the boost control solenoid?

Thanks for all this info......My AEM box is black in color. It was purchased new in 2006. I have a switch on the consol that Heffners put in for low boost setting or high boost setting. ( 93 octane on low boost and C-12 when going to high boost setting) I have never used high boost setting.

 

[britospeed]

Like others have said, setting up the 2 step will allow you to build boost instantly. The GT35's should spool instantly. Check the boost comp settings in the AEM under the boost control settings.

I use similar size turbos on my SRT and have full boost at 2200 RPM's.

 

[white out]

If you don't program the ecu; blirp the throttle, it will build boost at the line. But you will have to figure out how to bring the RPMs down when it comes time to launch.

Nick

 

[white out]

Also, I'm not sure what boost controller you're running. But the Hallman Pro RX with the ceramic ball helps with quicker spool.

I ran a GT35R82 on my STi (2.5 litre), so getting that thing to spool quickly was very important.

Nick

 

[utahviper]

With the 2 step setup up properly you can build boost at a stand still. You will need to learn how to make adjustments to the RPM within the 2step so you can play with it at the track. If you leave at 5k rpm with the 2 step you will be at maximum boost and probably blow the tires off. You probably need to leave around 3-3.5k rpm @4-5lbs of boost. You could probably hook that.

 

[Toma]

With the 2 step setup up properly you can build boost at a stand still. You will need to learn how to make adjustments to the RPM within the 2step so you can play with it at the track. If you leave at 5k rpm with the 2 step you will be at maximum boost and probably blow the tires off. You probably need to leave around 3-3.5k rpm @4-5lbs of boost. You could probably hook that.

This is what I was getting at with the boost controller question.

With today's modern controllers, you can have a "pre stage boost", Launch boost, then a time base boost curve etc.

Or even with a simple 2 stage with a manual valve and a gm solenoid, he can limit boost to say 10 psi on the launch, then switch to more etc...

 

[Russ M]

He does not need a boost controller his AEM unit will do everything he needs.

Roysviper,

Do you want to have someone do the launch control for you? Or are you looking to learn and do it yourself?

If you want someone to set it up for you its fairly easy to do, but you will have to email your tune which is easy to do if you have a laptop and an AEM com cable. If you need I can get you a tuner that can help you set it up over the phone, but Im sure its not going to be for free. If Heffner did the tune for you it should be easy to them to set it up and send you the right tune to load.

Let me know if you need contact details for a tuner.

 

[Roysviper]

The VCA has an AWESOME bunch of Great people in it. The responses from all you is greatly appreciated and a learning experience getting lots of good advice and input from alot of very knowledageable people. You all are what makes our club so great. I am proud to be associated with all you guys and NO......I am NOT ***!!!! Thanks everyone!!!!

 

[Roysviper]

He does not need a boost controller his AEM unit will do everything he needs.

Roysviper,

Do you want to have someone do the launch control for you? Or are you looking to learn and do it yourself?

If you want someone to set it up for you its fairly easy to do, but you will have to email your tune which is easy to do if you have a laptop and an AEM com cable. If you need I can get you a tuner that can help you set it up over the phone, but Im sure its not going to be for free. If Heffner did the tune for you it should be easy to them to set it up and send you the right tune to load.

Let me know if you need contact details for a tuner.

Russ

I agree.....Heffners did the complete install of everything. Soooo if my Son can't take what you guys have said here and figure it out then I will get ahold of Jason to get it set up...It would be nice to learn to do this myself but I for sure don't want to mess up the tunes he put in the AEM...

 

[white out]

He does not need a boost controller his AEM unit will do everything he needs.

Roysviper,

Do you want to have someone do the launch control for you? Or are you looking to learn and do it yourself?

If you want someone to set it up for you its fairly easy to do, but you will have to email your tune which is easy to do if you have a laptop and an AEM com cable. If you need I can get you a tuner that can help you set it up over the phone, but Im sure its not going to be for free. If Heffner did the tune for you it should be easy to them to set it up and send you the right tune to load.

Let me know if you need contact details for a tuner.

Unless the new AEM units are different than the '09 units (I haven't read into the updated features); he still needs a boost controller.

I agree that any high power AEM tuner can set up a good launch control (double step) for the car.

Nick

 

[Toma]

Unless the new AEM units are different than the '09 units (I haven't read into the updated features); he still needs a boost controller.

I agree that any high power AEM tuner can set up a good launch control (double step) for the car.

Nick

Aem can control boost. Boost by rpm is the typical set-up, I usually set up the wg duty cycle table (DC at a load versus rpm point)

It works, and it's ok.

I was just asking if that was what was controlling boost. And there are better drag race options out there though, the MSD unit is sick, as is the ams1000, but he can make do with what he has.

 

[white out]

That's interesting about the AEM. I am going to have to go do some reading.

Nick