S4s Boost Pressure

[Riddlemr2]

I just had the S4s code reprogrammed on my chip. What boost pressure should I be looking for? How long might it take the chip to re-learn the boost curve? Right now it spikes to over 1 bar, then settles down right around .75 bar.

[fmxa]

That's what my stock S4s chip did - after I put in a #5 it would hit ~1.2 BAR and fall back to 1.0 BAR. Boost never changes over the learning curve just the BLM values (I belive and Marcus or Sanj can correct here if I'm wrong!)

[Riddlemr2]

Hmmm...I guess I thought it would have been higher than that. It certainly feels fast, but now I'm starting to think I should have gone for a little more boost

[fmxa]

If you want fast throw in a #6, it's insane!

Hmmm...I guess I thought it would have been higher than that. It certainly feels fast, but now I'm starting to think I should have gone for a little more boost

[Paula&Marcus]

Dave,

The original S4s chip is exactly 0.97 bar max boost. But there should not be a drop down. If your engine is 100% you should see 0.97 bar sustained boost.

If it drops, please have a look at:

- ccooler system

- knock counts

- turbo

- wastegate capsule

- wastegate capsule adjustment

....

Cheers

Marcus

I just had the S4s code reprogrammed on my chip. What boost pressure should I be looking for? How long might it take the chip to re-learn the boost curve? Right now it spikes to over 1 bar, then settles down right around .75 bar.

Edited July 2, 2007 by Paula&Marcus

[Riddlemr2]

Dave,

The original S4s chip is exactly 0.97 bar max boost. But there should not be a drop down. If your engine is 100% you should see 0.97 bar sustained boost.

If it drops, please have a look at:

- ccooler system

- knock counts

- turbo

- wastegate capsule

- wastegate capsule adjustment

....

Cheers

Marcus

Marcus, could you elaborate on the wastegate capsule adjustment?

Thanks!

[Artie]

Marcus, could you elaborate on the wastegate capsule adjustment?

Thanks!

Dave,

Check your mechanical wastegate adjustment. With just a hose attached from the nipple on the outlet of the turbo the nipple on the wastegate, you should get about .65-.75bar boost. If it's less as I've been experiencing you need to adjust the length of the wastegate actuator arm. If you not quite getting .65bar of mechanical boost, then shorten the arm. Using a 7/16" or 11mm open end wrench slacken(loosen) the nut on the arm. Then remove the retaining clip on the end of the arm. Pull the arm off of the wastegate flapper tighten in the arm(shorten the length by turning clockwise) a couple of turns then put everything back as it was and take it for a spin. If you achieved you boost goal then you should be set. REturn the wastegate solenoid lines as they were and take it for a spin. If you haven't achieved .65bar keep tightening the arm until you reach the desired boost. This should keep your boost steady. Although I've been experiencing a dropping off of boost as well but haven't been able to adjust the wastegate any more so I'm replacing my exhaust system with a very low restriction unit in thought that my 2.25" exhaust piping is pinching off my flow!

Artie

[lotus4s]

One caveat on adjusting the actuator rod, be sure not to allow the rod end attached to the capsule to turn when loosening or tightening the nut or it may tear the diaphragm in the capsule...

[Artie]

One caveat on adjusting the actuator rod, be sure not to allow the rod end attached to the capsule to turn when loosening or tightening the nut or it may tear the diaphragm in the capsule...

OH, yeah, forgot to mention that! Thanks Jim

[Riddlemr2]

It worked! I'll likely tighten it a little more as it is still a little below where it should be, but I'll have to wait for it to cool down. Thanks for the advice guys!