Author Topic: I NEED some boost. Advice needed. (Read 2762 times)

DCC · « **on:** January 19, 2009, 06:14:23 am »

I have my trusty ol' mk2, and I have some thoughts... The engine is in good nick (it just passed 200.000 km or 120.000 miles), it starts fine, gets "quickly" to +100 mph and still sounds like a GTD should. The head and internals seem to be fine and the turbo is in pretty good shape too.

This engine is a JR engine, and it originally (when I got it) it was blowing 0.65 bar (aprox. 9.5 psi). After fitting the GTD/G60 intercooler, the pressure dropped to 0.6 bar (aprox. 8.7 psi). I didn't touch the fuel screw, but I noticed more black smoke than before (a petrolhead friend of mine warned me about that). Performance increased, though.

I'd like to get some more boost (kkk turbo unit). I don't need mega-performance. Which is better? I thought of the following:

- Bleed valve in the WG line.
- Bleed valve with a bypass electrovalve (so I can switch from the interior between stock and "overboost").
- Block the WG and set boost with the fueling (I have my doubts about this one).

Plus, how much boost is it reasonable with stock internals and fiber HG?

Thanks in advance.

molgrips · « **Reply #1 on:** January 19, 2009, 08:09:32 am »

Can't you just adjust the wastegate? 9.5psi is pretty lame

*disclaimer* I know very little about cars other than my own and not too much about that

saurkraut · « **Reply #2 on:** January 19, 2009, 10:20:34 am »

The waste gate has an adjustment screw, but it does almost nothing. I run the no-wastegate option. 25+ PSI all day, every day.

Fill the banjo bolt on the compressor with RTV and reinstall it. Unscrew the fitting on the waste gate and leave it in the hole. The waste gate will blow open from exhaust manifold pressure in the mid to low 20 PSI range.

Leave the fuel screw alone. Set you fueling with the LDA pin. If you don't have an preturbo EGT measurement, start with the lowest slope on the LDA pin. See how you like it. If you want more turn it up until you get just a little smoke. Your EGT should be OK.

Do you have a bigger than stock exhaust system? If you don't, do that first.

DCC · « **Reply #3 on:** January 19, 2009, 10:57:22 am »

Quote from: "molgrips"

Can't you just adjust the wastegate? 9.5psi is pretty lame

*disclaimer* I know very little about cars other than my own and not too much about that

Well, taking into account today's standars, it IS lame. :lol:

In ye old times they used to fit large turbos, now they fit smaller VNT's blowing at higher presures.

Quote from: "saurkraut"

Fill the banjo bolt on the compressor with RTV and reinstall it. Unscrew the fitting on the waste gate and leave it in the hole. The waste gate will blow open from exhaust manifold pressure in the mid to low 20 PSI range.

I guess RTV is some sort of silicone. Can a stock engine hold 20 PSI?

Quote from: "saurkraut"

Leave the fuel screw alone. Set you fueling with the LDA pin. If you don't have an preturbo EGT measurement, start with the lowest slope on the LDA pin. See how you like it. If you want more turn it up until you get just a little smoke. Your EGT should be OK.

Do you have a bigger than stock exhaust system? If you don't, do that first.

My engine and exhaust are totally stock. I was thinking of a slight improvement. Isn't the LDA (when stock) already in the lowest slope?

jtanguay · « **Reply #4 on:** January 19, 2009, 11:43:05 am »

Quote from: "DCC"

Quote from: "molgrips"
Can't you just adjust the wastegate? 9.5psi is pretty lame

*disclaimer* I know very little about cars other than my own and not too much about that

Well, taking into account today's standars, it IS lame. :lol:

In ye old times they used to fit large turbos, now they fit smaller VNT's blowing at higher presures.

Quote from: "saurkraut"

Fill the banjo bolt on the compressor with RTV and reinstall it. Unscrew the fitting on the waste gate and leave it in the hole. The waste gate will blow open from exhaust manifold pressure in the mid to low 20 PSI range.

I guess RTV is some sort of silicone. Can a stock engine hold 20 PSI?

Quote from: "saurkraut"

Leave the fuel screw alone. Set you fueling with the LDA pin. If you don't have an preturbo EGT measurement, start with the lowest slope on the LDA pin. See how you like it. If you want more turn it up until you get just a little smoke. Your EGT should be OK.

Do you have a bigger than stock exhaust system? If you don't, do that first.

My engine and exhaust are totally stock. I was thinking of a slight improvement. Isn't the LDA (when stock) already in the lowest slope?

a stock 1.6 might hold 20 psi. let the engine warm up first though (about half way on gauge). the 1.9 MLS gasket upgrade is a good idea though. with that i was running 20 psi no problem! possibly more as my gauge only went to 20 and i buried the needle a couple of times...

Smokey Eddy · « **Reply #5 on:** January 19, 2009, 11:48:18 am »

Definately suggest an aaz metal HG if you're engine is hydraulically lifted.

saurkraut · « **Reply #6 on:** January 19, 2009, 12:03:50 pm »

Yup RTV is silicon. I used Permatex Ultra Copper.

On the ther hand, it kind of putzy to get 15 PSI since the adjustment screw on the waste gate is useless.

I haven't run high boost with the peashooter exhaust in years. I suspect you'll be ok if you avoid smoke. Your EGT will probably go down. I don't remember where the stock LDA position was, so start at the bottom and work up. Just make marks with an indelable marker so you can put it back the way it was.

On mine, I have a 2.5" exhaust turbo to tail pipe. My fiber head gasket never gave a whimper. If i put my LDA at the lowest slope, I still get 20+ psi boost and it pulls pretty good. I beleve the EGT won't go over 1,000° F like that, so it should put less thermal stess on your engine while still giving you a noticeable improvement in power.

The nice thing about the RTV method is you just pic the silicon goop out of the banjo bolt, screw the waste gate line back into the waste gate, and your right back where you started. As we say here: 'it don't cost noth'n'

You really should do a big pipe first. You might get the boost you want that way.

The existing pipe is a crime against humanity.

Clintwalker85 · « **Reply #7 on:** January 20, 2009, 07:17:05 pm »

i'm tuning up my 94 vw golf 1.9 diesel (canadian model) now i'm not sure on your term "LDA" what its is....where is it....and how do you adjust it??

jtanguay · « **Reply #8 on:** January 20, 2009, 07:50:43 pm »

Quote from: "Clintwalker85"

i'm tuning up my 94 vw golf 1.9 diesel (canadian model) now i'm not sure on your term "LDA" what its is....where is it....and how do you adjust it??

its the spaceship thing on top of the pump. you need to crack open the cover (4 screws) to get to adjustment. the 1.9 pin in your LDA is sort of worthless... there is barely any ramp compared to a 1.6. you can either grind it down, or find a 1.6 pin.

Clintwalker85 · « **Reply #9 on:** January 20, 2009, 09:33:21 pm »

grind it down? how would i go about doing this?

dillenger1 · « **Reply #10 on:** January 21, 2009, 03:12:48 am »

you grind it down :lol: make yourself a slope like a cummins pin,but polish the crap out of it.

DCC · « **Reply #11 on:** January 21, 2009, 04:44:08 am »

Quote from: "Clintwalker85"

grind it down? how would i go about doing this?

The thing in grinding the pin is making a slope, in order to have some more fuel injected as the turbo pressure builds.

See number 8? That's the pin. Look at the shape it has (that's a 1.6 pin). Yours is almost straight, so there is not as much enrichment when the turbo blows.