turbo lag??? some turbo questions

[535is-pa]

im curious about turbocharging however i would hate to loose the bmw smoothness. and having been recently been given a ride in a old Porsche i have a fear of turbo lag.


i see that TCD is making some excellent setups. but other then power output how to they differ from bmw's own m106 in driveability? what about in comparison to the s38???

how is tcd's stage 1 setup on a stock b34 in comparison to the 745?

[altus22]

I only have experience w/ the S2, so all these comments come from that. Both from Todd's mouth and my experience in "the red car", the S2 is very linear, like the NA engine, just with twice the power.
The S2 has more torque, at a lower rpm than the s38. You can search for a number of dyno sheets for proof.
VS the m106, I have no idea, I've never ridden in one. The T04 in the S1 is much more powerful and doesn't die at the top end like the k27 on the m106 does.

[vance]

Also, the m106 is a bit of a dog until around 2300 RPM thanks to the k27. Also if you use the m106 exhaust manifold you will need to make some bushings for the studs, m106 are larger than m30. Spend the money, and go with Todd's stuff. Modern technology versus '80s technology. 80's good for pastel colored suits and Bren-Tens not turbos.

Vance

[535is-pa]

well thats good to hear about tcd's setups. a liner throttle response is what im after so i i guess im considering purchasing this setup alot more.

i drove that old Porsche today and i was horribaly deathly afraid of its lag. i nearly implanted the car into a tree when it kicked in and the insane understeer came out. unwinding the wheel seemed only to make it worse and i was quickly confronted with oversteer somehow, i was in the wrong lane pointing to another tree half sideways making all kinds of noise. and Lax was just laughing at me like i was my fault.

now should i do a engine rebuild? or just kill a few used m30's with boost?

[T_C_D]

Here is a a comparison of our 745i and our 535is. Both have the same basic engine. Both use Tial wastegates. Forget about the actual power levels. Loook at how much boost each makes at 3000rpm. The k27 on the 745i, like the k27 on that old Porsche, is a total lag monster.

[chrism]

Turbo lag dosent exist. What you percieve as lag is just your car running the way it always has untill boost comes into play.

The low engine RPM that the modern turbos TCD uses spool at all but eliminate the perception of lag.

[Bill in MN]

No appreciable turbo lag in my rig. I wouldn't worry too much about it.