Boost question

[jburnsinnj]

I installed a Duttweiller Neck on my stock 87' GN intercooler. I understand this will increase boost about 2 psi over stock setup. Now do i have to adjust anything like reduce the boost pressure back to stock to avoid detonation/knock.

I understand that this mod allows the turbo to not have to work as hard getting air through and helps it spool sooner but I am concerned about the higher boost causing knock . Can someone explain what i need to do now ?

I have a boost gauge and a computer analyzer (OTC) but will the increased boost hurt anything. I think I remember someone saying to install an adjustable wastegate lever to adjust the boost or would a custom chip adjust the boost instead of the adjustable lever?

The car has all stock components including the original computer chip but does have the following - fuel pump hotwire set up and Walbro fuel pump and adjustable f/p regulator, K&N Air filter in stock location.

 

[meanchicken]

You need to get an adjustable WG actuator on there.
It's always a good idea to loosen the WG actuator rod a couple turns any time you make an upgrade that will increase your ability to move more air and raise your boost.

I'd take it down 2 full turns, and then just creep up on the boost a turn at a time until you see the O2s in the 780-790 range or see knock.

If you start to see real knock (especially around the 70mph range) then either back the boost off a 1/2 turn at a time until it goes away, or if you get yourself a TurboTweak chip (please do this...simple and cheap upgrade and you'll appreciate the tuning features) add some fuel to compensate for the lean condition and get rid of the knock.

Where is you fuel pressure set?

 

[Red C5]

Run the best gas you can.

 

[meanchicken]

Yup.
If you live in an area where they still sell 93 octane, then stick with it and you should be good.

 

[jburnsinnj]

Fuel pressute is at 38 psi w/vac line off at idle

 

[jasjamz]

Make it 45 until you get the new chip.

 

[Razor]

IC shouldnt be on the first mods done to the car.

Open Element air filter, chip, adj fpr, adj WG, cat delete, exhuast, etc..

For me first mod is a scanmaster2.. that way I can check things before I start goofing with the car. Some old timers love that OTC.. thats on you.

 

[jburnsinnj]

What can a Scanmaster show that the OTC cannot ? What chip should I buy ?

The car has all stock components including the original computer chip but does have the following - fuel pump hotwire set up and Walbro fuel pump and adjustable f/p regulator, K&N Air filter in stock location, Dut Neck on stock I/C.

 

[jburnsinnj]

I cannot delete the cat as this is a daily driver subject to NJ State emissions testing and they look under the car and under the hood.

 

[Buix893]

Yea that CAT is killing you..lol...I live in NJ and never even heard of a CAT...:biggrin:

But honestly after removing the cat converter the car felt sooooooo much better, faster spool and pulled harder, not to mention better flow...turbo's love no restrictions

 

[Roger]

GN is a strange animal.

Local GN owner did not see any improvement with Dutt neck, but saw improvement with VR4. He had over 100 runs at Gainesville Raceway in Florida & was turning 11.5 (got thrown off the track - rollbar). Other GN owners see an improvement with the Dutt neck.

I saw big improvement with VR4, however, I never tried the Dutt neck.

 

["Turbo-T"]

I cannot delete the cat as this is a daily driver subject to NJ State emissions testing and they look under the car and under the hood.

Meaning they actually do the tail pipe sniffer test? Or could you get away with gutting the cat?

 

[Turbo RX-6]

I cannot delete the cat as this is a daily driver subject to NJ State emissions testing and they look under the car and under the hood.

Thats why they make test pipes that are good for 364 days out of the year. Your cat is only good for 1 day....Emission day....

 

[jburnsinnj]

What is a vr4 ?

 

[jburnsinnj]

What can a Scanmaster show that the OTC cannot ? What chip should I buy ?

 

[notacarlo]

scanmaster = live data while you drive mounted on the dash or over the radio.

Buy a TurboTweak chip, Full Throttle, or Jay Carter.

 

[Roger]

VR4 is a longer intercooler in stock location. VR4 is longer & the added length is added at the bottom. Almost double intercooling over stock, however, it hangs low.

 

[jburnsinnj]

Does anyone make a test pipe or better yet, a less restrictive than stock, replacement cat converter to bolt in place of the stock cat and exhaust system ?

 

[Buix893]

http://www.fullthrottlespeed.com

They have test pipes...$60 I think, just bolt it in and when ya gotta go for inspection put the cat in for the day, takes a whole 20 minutes to swap em in and out....

 

["Turbo-T"]

Does anyone make a test pipe or better yet, a less restrictive than stock, replacement cat converter to bolt in place of the stock cat and exhaust system ?

Test pipe...FULL THROTTLE SPEED - 3" Exhaust Test Pipe

Some companies do make high flow catalytic converters, but not sure how much performance you will suffer having a high flow cat vs. no cat.