Stillen Results...
 

Hey everyone,

We completed the install on our 370z using the Stillen Supercharger kit and 9lb pulley.

The car produced 475hp at the flywheel and 340 ftlb torque.

When we went to tune the car on Tuesday we had issues for a long time trying to balance the voltages at idle and just above idles and when coming off throttle.

We eventually balanced the MAF's by rerouting the pipe work down beside the charge cooler pump in the driver side/left side of the front bumper.

Once we got up and running we found the car to only be producing 7.5psi.

Our setup is as follows:

Stillen SC kit
25 row oil cooler
9lb pulley
MXP Exhaust
Decat/Test Pipes
Custom Tune from TDI North

My theory on the 7.5 psi is the decat/test pipes creating no back pressure. Would anyone tend to agree?

I have CSV file from logs from the day after doing a few pulls but i cant seem to attach it here?

Can anyone chime in and let me know what they think? I would have expected the car to do well over 500hp at the flywheel.

Cheers

Just out of curiosity where are you reading boost from?
The TP should not really cause an issue, most guys run the same setup without boost loss. My first guess would be a leak somewhere, did you ever see the car hitting 9PSI prior to re-routing the pipes?

No the car never hit 9psi at all.

We are measuring boost directly off the inlet manifold.

Would you suggest a smoke test?

I would do a leak test to start, my only other thought I know this was with the rotrex units (GTM kit) but not sure on the vortech units. Need to run the SC for so many "miles" or time to break it in and get it spinning fully.

I'll perform a leak test tomorrow to see if there is a leak anywhere in the system. I know the charger needs the oil dumped at 1000 miles after the break in point.

Any other ideas?

I am unfamiliar with the UK. At what elevation are you guys at? Elevation will affect both power and max boost.

Elevation at mapping was 13m from sea level.

Fuel used was Shell V-Power Nitro 99 ron (equivalent to your 93)

Any help is appreciated.

Boost can be thought of as resistance to airflow, so yes, you might lose boost, but should not lose power, with a freer flowing set up. Are you sure you are down on power or just boost pressure?

How are you testing it at the flywheel?

Careful...your motor is about to blow !!! :eek:

Ask me how I know.

It may be that the supercharger isn't reaching its efficiency range fast enough without some type of baxkpressure. This is definitely a documented issue when running a very free flowing exhaust with centrifugal Superchargers. What does the dynosheet look like and what type of Dyno was used?

pics of your new inlet piping you may have choked the charger

Here is a data log of the car as well.

I assume it is on an engine dyno (i.e. engine is out of the car) rather than a chassis (rolling road) dyno, otherwise there would be a correction factor for drive line losses, or the OP has confused flywheel with "wheel" figures. I guess we'll get feedback in due course.

No its on a chassis rolling road. I have no idea what the correction factor is but thats definitely the power assumed at the flywheel. I double and triple checked.

Do you know the WHP?

No idea. I have emailed him to ask but won't get a reply until tomorrow as its 23:12 here just now.

Has anyone got any feedback on the log?

I know its rich but Stillen also commented on the timing.

It's not on the stillen tune is it?

I have the same kit with 3" cat back and tp. I also have the 9lb pulley and mine only makes 7psi. I think that's just what this pulley makes! The only way I think to make more boost is to change the pulley on the blower.

Custom tune. It started on the Stillen International Base tune which is good enough to start and move around but useless other than that.

Good I'm happy with my Stillen product but the caned tune sucked on my car.


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I'm confused. Are you concerned that the S/C isn't creating the advertised boost or that it's not generating the advertised power or is it suddenly making less power and or boost than previously measured?

Boost values are all based on the capacity of the blower. the size of the pulley, and the engine (including intake, exhaust, IC plumbing, and valve timing) -- if you have something set up differently than Stillen had when they took those measures, you will get different results.

As to power, unless you are finding evidence of a loss as compared to an earlier run on the same dyno, I would guess that tuning bugbears aside, your car is putting down power and torque figures in line with expectations.

again and sorry of I missed it but is this WHP or engine power?
"The car produced 475hp at the flywheel and 340 ftlb torque."
The TP's will cause you to have lower boost as said before but the WHP numbers shouldn't be down? You should be making the same power just at lower PSI,
Only thing I can comment it why TP's? I stayed with the stock cats and made over 450WHP( 457) but I changed some things and one of them was not the pulley. I would toss the stock cats back on , unless you want to keep the boost down under 10 since it seems a some of us had issue with engine failures with PSI over that. I did :/

And Why did you move the charge pipe? I didn't have any idle or off throttle issues and had an upgraded BPV. I did how ever have UPREV MAF's tho.

It was where the air filters were sitting that we had to move. The MAF voltages were unbalanced when you put the big fan on it like you were driving.

The only cats I have are Berk Sports cats. If I put them on I am assuming I am going to have to tweak the map?

Alternatively, would putting restrictor rings in the exhaust help lift the pressure?

If the MAFs were unbalanced I would guess you left the plastic piece off that mounts to the bumper and blocks air from the lower filter. The guys who installed mine did that.

Nope, it was a metal shield and I did the installation myself and did everything in the instructions.

We then ran tests on the MAF, tried new ones, tried different positions monitoring. Only balanced place we could get was left side front bumper.

You did better than the shop that installed mine then. I had to build my own because that one wasn't wide enough, If I coasted down an off ramp air would get around it so I made a wider one the that wraps below and up behind the lower filter and haven't had a problem since.

My mafs did this too, I bought a 5" Plastic plant pot, got it at home depot. 7 $.
Cut it in half, placed them on the back side of the filters, against the rad. When my fan was turning on, it would give my MAFS a weird reading. This fixed it.

OK some updates for you.

I smoke tested the car going directly into the inlet manifold and we have zero leaks. Pressurised the system enough that it was bellowing out the air filters.

Im going to go with the decats are causing a drop in boost and thus a drop in power.

Did you ever find out what the WHP is?

That's not exactly the way to think about this... you can make less boost, and more power, provided the mixture is timed to combust optimally.

BUT... if the mixture is blowing out too quickly (i.e., before peak torque is made in-cylinder) then VVEL timing tuning is in order.

Think of this in terms of optimal cylinder filling -- too much restriction is no good, too much flow is no good. It's gotta be just right.

That said, adding a mechanical "choke" is almost definitely less desirable than adjusting valve overlap.

pressurized the system enough that it was billowing out the air filters sounds like it wasnt pressurized at all. to do a pressure leak test you should have capped the exhaust, plugged the intake brought the piping up to the rated 10 psi to find leaks under pressure.

This makes sense. :iagree:

The problem I am having here is that no one has mapped a setup on this engine like this in the UK before. TDI who mapped it are VERY good but this setup I feel requires specific knowledge of the engine. I couldnt have asked any more of TDI, they went above and beyond on the day :)

I have sent Motion Lab a PM to see if they would be happy to remote in when the car is on the dyno to alter/tweak the map. Hopefully they will get back soon.

Can anyone else recommend someone who might be willing to do this? :tup:

I'll get my coat...

Do it again in the morning. You can tell im not on the tools. Ever.

I'm sure Alex and Todd will help out . They are very much stand up guys. They are remote tunning my car now and have helped me in the past with my Stillen SC kit tune also.

If the results show no leaks and the car is making the correct power then I would not worry about the PSI level. Remember that using less boost and making equal power just means the system is running efficiently.

But I agree with others, if you have major concerns you can always do remote tuning with a shop to look over the car.

the other bosst related thing to check would be belt slip, make sure the ensioners are tight but don't overtitghten them or you will blow out the bearings in the jack shaft and input side of the charger(or go cog belt drive)