Sloooo4esT

I have not yet installed my stiffer spring, so tonight we put it in friends IA chipped 200 20V. his car was normally running 19 psi, after spring it spiked once at 28 psi, drove for a while as computer adjusted to the new mod and the car consecutivly hit 25 psi and smoothly too, it was a noticable differance, was hitting 25 fast and dropping off sooner than it did with the old spring. car also backfired more, which sounded sweet, but pulled without any bucking. one pull started at 2400 rpm boost hit 21 and jumper to 25 and we could feel it, but going WOT over 3500 prm was smooth. spring was set with no threads showing. we both were supprised at the results.

now what I do not understand is why the max boost increased by 6 pounds? I thought they were not supposed to raise boost level. makes me weary of putting it in my S6 cause I am already running 24 pounds w/ MTM 1+.

has anyone figured these springs out yet and why so many people are having differant results with them, is it safe for my car? (sorry for dumb question)

Wahhab

I had bought one of those springs from 034, and it made the car go like crazy initially. I can't give you PSI numbers because I don't have the boost gauge connected yet. After the car reached about 5500 rpm, it had a sudden and violent cut off. The best we were able to figure is that I am running MTM1+ software with rs2 turbo and rs2 IM. I decided to remove it until I get the rs2 injectors and correct software. I am on a small budget now since I moved to Texas. Actually, I take it easy on the car too.

AndrewWK

good Idea to back off. Be careful running that setup as it's very easy to run lean and your o2 sensor will make this very obvious when you finally get your upgrade completed. I actually used the stock software until I had the eeproms to accompany my injectors.

Andrew

VR_Life

Q: Why more BOOST ?
A: Stiffer WG spring increases the pressure necessary to open the Wastegate. Since the pressure to open the WG is the boost pressure steered from the turbo compressor into the WG by N75K solenoid this means that it takes a higher boost to counter the force of the spring and open the WG (also called the "WG crack pressure").

This is why the end psi achieved by compressor is higher.

Q: Why the spikes ?
A: Normally the ECU flutters N75K solenoid with a duty cycle based on boost detect at the MAP sensor (closed-loop feedback control) to achieve a constant desired boost level goal.

Since the turbo now reaches a higher boost before the WG has the intended effect, it spikes and it takes a while for ECU to apply more duty cycle control. It doesn't seem to be adaptive so spikes are going to be a permanent problem unless you put a manual boost controller in parallel with N75K (like me ;-) to clamp the boost.

Q: Why the bucking / cut-out some folks found
A: I think there are two issues at play here.
1. I suspect the cut-out is caused by the ECU Boost Controller panicing when boost increases too fast, or the higher boost level is not being matched by fueling, or if the knock control limit is reached. I believe it cuts fuel using the FP relay, and there is actually a signal post that I can use to observe if this happens but have not had time to confirm this for sure since my cut-out issues were cleared up with replacing sensors and haven't come back.
2. I believe some folks are hitting the boundaries of the K24 & RS2 compressor efficiency by effectively decreasing the RPM at which higher Boost levels are requested. When you get below the left PR line of the Compressor it will cause the turbo to surge, which feels a lot like bucking.

I was *never* lean, and never had any audible pinging, but some issues cleared up much better after replacing my Knock sensors. It still has issues though and I will be bypassing my FP relay, if something else turns up I will try and report back.

Sloooo4esT

spike once in the learning curve of the ECU.

so you think that installing this spring in my car will also increase the max boost level. my car normally behaives like the 200 20v is now with the stiffer spring

think free flow exhaust like stromung will have any positive effect on running conditions with stiffer spring?

and on another note, how recent is your bluetooth modification? it's with Motorola? have a write up?

thanks

Sloooo4esT

because both give the same result of higher spring rate correct?

repeater

So where in Texas?

Wahhab

Austin it is

UrS695

I think the stiffer spring has more force than tightening the stock spring down.

If you pull the electrical plug on the FV and drive the car the boost pressure will be the pressure that the WG spring provides.

I have done this with the stock spring cranked all the way down as far as it would go (and with a washer shim) and I was seeing about 8psi. With the 034 spring (and FV plug unplugged) I was ititially seeing about 14psi and have since backed off the screw for about 11-12psi.

It would be interesting to know what types of boost pressure people were running with the 034 spring (or stock spring for that matter) and the FV unplugged. I had to back the 034 spring off to about 11-12psi in order to prevent the bucking with the FV conected which I am at about 20psi peak and 18psi sustained with MTM Stage1.

UrS695

I have had the 034 spring in for a few months and have noticed an improvement in mileage. Don't know what else to blame it on as nothing else has been done to the car and commute is the same.

I used to get 390-410miles to a tank with an occasional miracle tank that would go 420miles. With a 17.5 to 18.5 gallon fillup this was about 22 mpg.

I have recently gone 4 or 5 tanks of gas in the 440-450mile range and had a miracle tank that went 454 miles on 17.9 gallons for 25.4mpg.

Anyway, was wondering if anyone else noticed this with the 034 spring.