Zep's Underwhelming VF 540i

[Zep]

Hi All

Having had the supercharger kit on for a little while now, and having ironed out a few issues I finally took my 540i to the local 1/4 mile.

I have had the car dyno'd previously but I was quite dubious of the outcome because of the ease of fudging them to make customers happy (and I was right). Supposedly made 335whp on a Dyno Dynamics machine with the kit and 235whp stock as rock.

The tune provided by VF is not particularly good and after asking them to fix it they have now decided to just not respond to my emails anymore. Which is OK as they are useless and would warn others to be weary of purchasing any of their products.

Anyway, I took the car to the local drags when I first got it just to see what it did as a baseline.

Timeslip 2013.jpg
14.2 @ 96mph with no spare and about 1/2 a tank.

So with the supposed extra 100hp of the $6000 VF supercharger kit it just now ran this:

Timeslip 2015.jpg

13.7@102mph......yawn.

Mods on car:
M60 Manifold
AEM methanol injection
Larger K&N Air Filter

$6000 for .5 seconds of the ET and 6mph is not right. True I could have gone for a few more runs when the temperature cooled a bit (was around 27oC/80oF) and picked up maybe .2 of a second off but didn't have time. I managed 3 runs with them all around this result.

I intend to replace the auto with a 6MT but will need to run with the step auto for at least another year. The shifts are terrible and I am sure better software like the Alpina TCU flash would significantly improve the ETs but still its a poor effort as far as I am concerned.

I have already paid TTFS for a remote tune for the 3.25" pulley and 42# injectors so hopefully finally will see a proper tune for this car. I cant do headers as I cant afford to sink that much cash into a car like this but I will be making the horrible stock manifolds a bit more free-flowing prior to the TTFS tune.

I am so disappointed with this effort that I am determined to pull all the stops to make this old barge as fast as possible. I will be updating the progress here for all those interested and to help those that follow this path. I have already received a lot of great help from the threads and want to give back what I can.

[BMW540san]

If I were you, I'd strongly consider doing the full custom exhaust with Supersprint headers and HJS cats. While I have no experience with VF I did hear positive and negative although it seems more negative lately.
I've read few good exhaust technical articles from reputable sources and stock exhaust is simply inadequate to handle increased HP and torque from FI.
If you're modifying car like 540 you can quickly surpass 100% value of the car with the cost of few mods.
So you either sell it and buy something that's much cheaper to modify or you go crazy like some of us and just enjoy the car.

[Cereal]

Do you have stock rear end our do you have limited slip/posi?

I think m5s do about 13.2 @107 so maybe your are just struggling of the line?

[philly98540]

Is that reaction time right? Sheesh. 60' looks OK, so somethings off with the RT I think.

Anyway, you still have the 3.8" pulley, and your making about M5 performance and that is what the kit is designed to do. So not bad, but seems less that what others are getting. You need some AFR plots and some more data like timing, to help us see better whats going on with your car.

Are your cats original and stock? Maybe they are starting to cause excess backpressure on the top end. Who knows with some data.

I'd check exhaust, then do the 3.25" pulley and tune stuff. You can get some more power for sure.

[evomel]

well this is why I decided to stay naturally aspirated!!!!!!! I'm dynoed at 300 RWHP and with no REAL NUMBERS from VF to say exactly how much more anyone could really gain realistically for $6K ------its at the biggest waste of $$$$$$$$$$

[ryanc528]

This is very interesting as I have been considering going VF recently...Sub'd

[Zep]

If I were you, I'd strongly consider doing the full custom exhaust with Supersprint headers and HJS cats. While I have no experience with VF I did hear positive and negative although it seems more negative lately.
I've read few good exhaust technical articles from reputable sources and stock exhaust is simply inadequate to handle increased HP and torque from FI.
If you're modifying car like 540 you can quickly surpass 100% value of the car with the cost of few mods.
So you either sell it and buy something that's much cheaper to modify or you go crazy like some of us and just enjoy the car.

As much as I would love to have a set of decent headers I am afraid that it's just not feasible for me. I had the option of headers or going with the VF kit and chose the latter. If there was another group buy for a decent price I might reconsider but certainly not on the radar at the moment.

I am going to be removing the cats in the stock manifolds and replacing the rest of the exhaust system back from there.

- - - Updated - - -

Do you have stock rear end our do you have limited slip/posi?

I think m5s do about 13.2 @107 so maybe your are just struggling of the line?

I have the 3.15:1 5AT non-LSD.

The expectation, whether wrongly or rightly was to achieve a result somewhere on par with a stock M5. My launch was average but the overall MPH of the runs dont really reflect VF's claims of 100hp+.

[Redshift]

I'm pretty happy with my VF setup, despite all the issues. Custom tuning, smaller pulley, and headers are really helpful but you should still be fairly excited by the stock VF kit. I mean, there is no other way to get 100-120hp more from an M62 other than this or nitrous. Evomel, your stock dyno numbers are irrelevant - it's the difference you'd get by adding a supercharger that matters. On that same dyno, adding a VF blower would give you the same gains as anyone else.

Once properly tuned, and after understanding what you are getting into, I would say the VF kit is very solid. You just have to know what to watch out for, what to improve upon, etc. Many of us with VF kits and headers and smaller pulleys are making at or above 500hp at the crank. That's pretty spectacular from an engine that was designed in the mid 1990s and is only 4.4L of capacity.

[Zep]

Is that reaction time right? Sheesh. 60' looks OK, so somethings off with the RT I think.

Anyway, you still have the 3.8" pulley, and your making about M5 performance and that is what the kit is designed to do. So not bad, but seems less that what others are getting. You need some AFR plots and some more data like timing, to help us see better whats going on with your car.

Are your cats original and stock? Maybe they are starting to cause excess backpressure on the top end. Who knows with some data.

I'd check exhaust, then do the 3.25" pulley and tune stuff. You can get some more power for sure.

I wasnt really trying to race, rather to test the power output. The track marshals barely gave me any time to brake boost off the line hence the delayed RT. They tend to try to rush people through so they can all go home.

Cats are stock and no doubt very restrictive but arent long for this life and will not be a problem when I get the tune by TTFS.

I have logged and logged and logged and sent the data to VF showing that fuel is not enough and that timing is down. Trims were always climbing to ~15% indicating that the tune just wasnt providing the fuel required. I replaced the fuel pump, filter and FPR and MAF and the only cause of the poor fuel situation was the VF tune and they made little effort to rectify. And I am not alone with that problem.

[Redshift]

Just one note, trims only indicate an issue with part throttle, not full throttle. At full throttle the car is using maps, not sensors, for fueling. So the logs at full throttle and AFR at full throttle (ideally you'll get a graph of AFR versus RPM) tell the story.

Part throttle could use some tweaking if your trims are high (or, there could be other issues like spark plugs, o2 sensors, injectors, vacuum leak, etc) but if you are running good AFR at full throttle then VF has done their job at least most of the way.

[joekitch]

aaaand this is why i'm excited by toolman02's experiments with jaguar blowers.
VF being the ONLY game in town for m62 superchargers bugs me greatly.
toolman still hasn't dyno's his monster yet though, the lazy bum. at some point i'm just going to set up and PAY FOR a dyno appointment FOR him

[Zep]

The physical VF kit itself is not bad, however the tuning and installation instructions are just woeful. I received just one revised tune before they decided "nope, that's the limit of our customer support". I provided dyno plots and logs of WOT and average street driving and the single revised flash I received made no difference. I can appreciate the difficulties in dealing with customers and their cars that are many miles away, and in unknown conditions but just deciding to no longer respond to their emails is utter crap business ethics.

I can only suggest that if you are considering a blower kit, treat the VF package as hardware only and source a good tuner to handle the software.

- - - Updated - - -

Just one note, trims only indicate an issue with part throttle, not full throttle. At full throttle the car is using maps, not sensors, for fueling. So the logs at full throttle and AFR at full throttle (ideally you'll get a graph of AFR versus RPM) tell the story.

Part throttle could use some tweaking if your trims are high (or, there could be other issues like spark plugs, o2 sensors, injectors, vacuum leak, etc) but if you are running good AFR at full throttle then VF has done their job at least most of the way.

From what my logging suggests, fuel trims may not affect the maps used for WOT but the trims are affected by the AFR of WOT.

I have been cruising at 2000rpm and monitoring a stable LTFT at 5%, then go WOT for 5 seconds and then drop back to 2000rpm. LTFT are now at 10% and climbing.

[DanB]

My fully tuned Dinan S/C got 13.3@108 in the 1/4 mile and that was on race gas on a warm but not too hot day. My car was the R&D vehicle for Dinan's pre-vanos 540iA.

[philly98540]

The cats may be choking you up top. Let's see what it does after those are tested or you upgrade them.

[geargrinder]

Zep thats a bummer but something is not right. You should see much better. Hang in there and try to debug.

well this is why I decided to stay naturally aspirated!!!!!!! I'm dynoed at 300 RWHP and with no REAL NUMBERS from VF to say exactly how much more anyone could really gain realistically for $6K ------its at the biggest waste of $$$$$$$$$$

Uh no Mel you are talking out your ass.

All guys on this thread have dyno'd solid numbers. And have excellent fast cars (well ok Zep is still dialing in).

above 500hp at the crank. That's pretty spectacular from an engine that was designed in the mid 1990s and is only 4.4L of capacity.

Bri PLEASE dont quote estimated crank numbers. Thats the kinda thing that gets you laughed outa town by the real big power guys. RWHP on a non-fluffy dyno is what is rock solid - let people make their own judgements on what the crank might be, but power to the ground is undeniable.

Basically a solid smaller pulley VF setup running well should put down a solid repeatable daily driveable 380-400 RWHP or more depending on supporting exhaust and other mods and depending on era (slight more top end for the non-TU, fatter curve but maybe lower dyno queen number for the TU).

"Fact not opinion" as they say.

[evomel]

God bless you all

[RoundLightsRule]

Years ago a former boss I worked for built a custom vortech based SC set up on an 840i, at Denver elevation (5280+-) the healthy e31 spun the rollers to something like 165WHP, with auto trans chip from someone I forget (dinan maybe?) and cat back exhaust from maybe magnaflow? this is almost 10 years ago. The charger was a self contained unit with a air to water IC , I forget the pulley diameter but boost was roughly 5-7psi and we saw just over 300WHP, 305-315 IIRC. Stock engine management with a RRFPR, cant remember if the injectors were stock. Im sure plenty of power was left on the table using the RRFPR and stock management. Glad to see people going to the track with these cars!

[jstern]

Zep, I think that you must have patience and you must forget about VF giving you any help. You're right that the VF kit itself is not bad but their tunes (hahaha), their knowledge about our cars and their customer service is beyond terrible. At least that's my experience. I bought and installed my kit during the Summer of 2011. The car had CEL's for rich running for months to the point where VF had me restore the DME to stock and then I sent it back to them for a new tune. They kept it for 3 weeks saying that they wanted the tune to be right. When it came back to me, the CELs continued. I gave up on VF and began doing research and solving problems by myself.

When I finally got a tune at Frank Smith's in Jan 2014, he told me there was absolutely no tune in the DME. The only VF mod was resistors in the MAF signal line worth 400 ohms. The only thing VF did to the DME was adjust the top speed, top rpm and the top torque limits higher. Frank fixed the "tune" and the car has been wonderful since. But I keep making adjustments (installing a high flow exhaust system including headers and a bigger air filter thanks to your post on Redshift's build thread) and the car just gets better/faster. It is my opinion after doing some reading in the FI forum that it takes a while to get things right. It's sort of typical that VF is an inexpensive way to start but it take longer to get what you want. If your 540 is performing like an M5, you've got a good start.

[Zep]

Thanks for all your responses. I am hoping that the new tuning will sort out the lackluster performance issues.

Since running the strip the other evening, I decided to visit a few exhaust shops to get some quotes/estimates for a better system. I took my galaxy tab which I use to monitor fuel trims and was astounded to see them sit between 4-7% Bank 1 and 0.8-3% for Bank 2, no matter how aggressive I drove. This is quite different to how they have been, at least half what they usually are and the lowest I have seen since the S/C was installed. I did clear all adaptations prior to driving to the drag strip so perhaps the car wasn't properly adapted to the parameters for those 3 runs and have only now settled?

Either way I am confused as to why the trims are looking so much better?

I was quoted $1800 for a 2.5" header back system with aftermarket 'Hi-flo" cats, which I am not particularly impressed with. I was hoping to get the pre-cats removed from the stock headers at the least but 3 shops didnt want to do it. The aftermarket cats they use are crap and will likely just fail in no time. I might just go with a $900 quote to fix the cat back system with 3" pipes, then order some HJS or similar proper hi-flow cats and just get them to weld them up.

I am also now thinking of buying some of those Schmiedmann headers and having them modified to clear the steering rack, which would set me back about $1500 all up. Not really wanting to sink that much cash into this car as I pretty much out-of-love with it now and looking into the next project.

[mapleridge]

looking forward to see how the changes in variables improve your performance.

[mcgnms]

I do not want to sound pessimistic or bad, but if the car feels slow after the VF kit then look into installation issues, not tune issues. We like to bash the stock tune for a few things, but it ran fantastic on my car and for many months and I drove it hard with no issues. The car was tremendously faster than naturally aspirated. It can be felt and seen from idle to redline. I had zero problems with their tune or kit. Its not easy to install, but if it is done correctly then it works. Moreover, the tune I had was designed for an otherwise stock car. It still ran very good.

A 102mph trap is no doubt underwhelming. I have seen N/A 540i's do better. The 60' is decent also. I would look into other issues. The temperature and pressure at the track listed on the slip is decent also.

Lucky for you, I just dropped my car off at TTFS with the Bosch Green Giant 42lber's so I will be the guinea pig and it will likely help them in getting your remote tune working quicker/better (same with Brian if he chooses this route). Mine should be done Tuesday, maybe Thursday. I talked to them about your car so lets hope this turns it into the successful trio.

When you swap the injectors, the car will struggle to start (if it can start at all). They will likely have you upload a file before you even start it.

Cats are stock and no doubt very restrictive but arent long for this life and will not be a problem when I get the tune by TTFS.

You would be surprised how much of a problem a restrictive converter can be. The mass of air that can pass through a certain volume of space has a limit. The stock converter was designed with a limit in mind. That is why it has a certain diameter and density. An S62 used larger converters. At a certain point with enough flow, backpressure will build and cause heat and reduced power. This effect under boost can be significant.

I have logged and logged and logged and sent the data to VF showing that fuel is not enough and that timing is down. Trims were always climbing to ~15% indicating that the tune just wasnt providing the fuel required. I replaced the fuel pump, filter and FPR and MAF and the only cause of the poor fuel situation was the VF tune and they made little effort to rectify. And I am not alone with that problem.

I think somebody mentioned before, this is closed loop. Once again, I did not check closed loop trims, but my AFR's were at 14.7 where they need to be. That is what matters.
The bottom line is their tune works. It worked for me, RedShift, and Philly98540. I have not driven the other cars, but on my car it was absolutely nothing to complain about.

I recommend looking into other issues such as installation of other engine issues that can effect this.

[geargrinder]

When I finally got a tune at Frank Smith's in Jan 2014, he told me there was absolutely no tune in the DME. The only VF mod was resistors in the MAF signal line worth 400 ohms. The only thing VF did to the DME was adjust the top speed, top rpm and the top torque limits higher.

Yeah John there's an interesting thing there.

I also had another tuner look at my tune and say it looked nearly stock.

But I am (and you probably were) on the old "GIAC" tune that was outsourced by VF.

Last year or so VF acquired a tuner operation called "hex tune" that was supposed to be all new tunes, it's unclear how much that is true, if so how much time went into them, how they did the transfer etc.

On the 540's they ARE different and have to be as they now use manifold referenced fuel pressure regulators... but also does seem they aren't that great as Frank seems to be getting gains...

Still more to come as some other guys get their cars done by Frank...

[Zep]

I do not want to sound pessimistic or bad, but if the car feels slow after the VF kit then look into installation issues, not tune issues. We like to bash the stock tune for a few things, but it ran fantastic on my car and for many months and I drove it hard with no issues. The car was tremendously faster than naturally aspirated. It can be felt and seen from idle to redline. I had zero problems with their tune or kit. Its not easy to install, but if it is done correctly then it works. Moreover, the tune I had was designed for an otherwise stock car. It still ran very good.

A 102mph trap is no doubt underwhelming. I have seen N/A 540i's do better. The 60' is decent also. I would look into other issues. The temperature and pressure at the track listed on the slip is decent also.

Lucky for you, I just dropped my car off at TTFS with the Bosch Green Giant 42lber's so I will be the guinea pig and it will likely help them in getting your remote tune working quicker/better (same with Brian if he chooses this route). Mine should be done Tuesday, maybe Thursday. I talked to them about your car so lets hope this turns it into the successful trio.

When you swap the injectors, the car will struggle to start (if it can start at all). They will likely have you upload a file before you even start it.

You would be surprised how much of a problem a restrictive converter can be. The mass of air that can pass through a certain volume of space has a limit. The stock converter was designed with a limit in mind. That is why it has a certain diameter and density. An S62 used larger converters. At a certain point with enough flow, backpressure will build and cause heat and reduced power. This effect under boost can be significant.



I think somebody mentioned before, this is closed loop. Once again, I did not check closed loop trims, but my AFR's were at 14.7 where they need to be. That is what matters.
The bottom line is their tune works. It worked for me, RedShift, and Philly98540. I have not driven the other cars, but on my car it was absolutely nothing to complain about.

I recommend looking into other issues such as installation of other engine issues that can effect this.

I know what you are saying and have thought that too, but I have taken the car to be looked over by a third-party mechanic and then again by the mechanic that installed it in the first place, and they couldn't find any specific faults or install issues (not to say they dont exist). I have had it dyno'd a few times and the verdict has been that fueling is an issue and should be dealt with by a better tune. I can only go off what info I get from the professionals.

The car doesn't have any drive-ability issues and feels strong but the effort at the strip didnt reflect that perception. It gives no trouble except for the odd warmish starts (where it has cooled down after an hour or two and then has a slow re-start). This has greatly improved since I have reinstalled a lot of parts, changed plugs, tightened connections, replaced fuel filter, pump etc.

There haven't been any fault codes thrown except a few misfires at startup, which have been due to fouled plugs. The only odd thing I have been able to find have been the fuel trims, which increase with load and not at low rpm or idle - which doesn't indicate a vacuum leak.

Here a few snapshots of the logs I have been recording over the previous months since installation. The program I use is "Torque Pro" and it isn't the greatest but it can only display the data provided to it from the DME so its useful to see what is going on. In July, the trims were quite high and hitting over 20% at one stage. Then after doing some improvements as mentioned before, they were sitting around the 12-14% for bank 1/8-10% bank 2.

When you go WOT, the logging would show a dip in the LTFT but not be 0%.

Then, for some unknown reason trims are now maxing out at 7% bank 1 and 3% bank 2, no matter the load. In the last WOT run on the list, the logs show that bank one drops to 0% and bank 2 stays a .7%, which is weird (and even though the TPS is 23% I can assure that the pedal was firmly planted, there is just a bit of lag with the logging). I totally understand the closed-loop system at WOT and that pre-programmed maps are utilized, but these logs suggest that the DME is referencing trims or doing something to affect trims during WOT. I cleared the adaptations prior to going to the strip on Wednesday and drove about 20miles there and back so they have had some time to adjust. There is a chance that clearing the adaptations could have impacted on the performance of the car at the drags but I think that's unlikely.

TRIMS.jpg


Anyway, I am glad to hear you are getting your car tuned soon and look forward to benefiting from your guinea pig status.

[mcgnms]

Now that you mention sluggish warm starts, I had the exact same problem. Cold starts and hot starts were fine. Warm starts sometimes were strange. Nothing to worry about though. If you want to start diagnosing, we need real numbers here. WOT AFR's, vacuum/boost, RPM's, Fuel Pressure...etc.
When was the last time you replaced the fuel pump and the fuel filter/regulator assembly?

[Zep]

Now that you mention sluggish warm starts, I had the exact same problem. Cold starts and hot starts were fine. Warm starts sometimes were strange. Nothing to worry about though. If you want to start diagnosing, we need real numbers here. WOT AFR's, vacuum/boost, RPM's, Fuel Pressure...etc.
When was the last time you replaced the fuel pump and the fuel filter/regulator assembly?

The guy who installed the kit says that the slow starts are due to excess fuel and that its fouling the plugs.

Here are two dynos plotting boost and afr over power. The ink line on the AFR is what the mechanic said they should be if the tune was better. Boost is about 5.3psi@6100rpm.

12.jpg

AFR.jpg

Fuel filter and FPR were replaced about 1 month ago and the pump replaced with the S62 pump 2 weeks ago.