Bugatti Veyron....It's what's for lunch.


ChipBeck

GT Owner
Staff member
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 13, 2006
5,783
Scottsdale, Arizona
Gentlemen,

After not getting any runs in at GT Speed Day I decided to return to Mojave last weekend for the Mojavi Mile. I had not run my GT hard since getting it back from the GT Guys with my Accufab freshened motor and I was looking forward to trying out the C-16 tune. Another motivation was provided by Car & Driver Magazine who was bringing a 2012 Bugatti Veyron along with several factory techs who would make sure it performed well. In the abstract I knew my TTGT should be faster in the standing Mile than a Veyron but who could resist a same day heads up contest? Sounds like fun.

The Bugatti arrived with great fanfare, multiple photographers, and was swarmed at tech inspection. After Jack's tragic accident 2 weeks earlier the fire and emergency crews put my GT (and me) through the wringer but I finally emerged with permission to run up to 235 MPH. That should be plenty even if #34 ran lights out. So how did it go?

With a DA of 4500 feet and a slight headwind my first run was 212 MPH and my car wasn't pulling well in 5th gear. Something wasn't right but I couldn't put my finger on it. 2 more runs, another 212 and a 213. Respectable speeds at a high altitude Mile but #34 was not putting out a winning effort. Still, the Veyron made 3 passes with a best of 201, and got slower with every pass dropping to 196 and then 191. Car & Driver wanted to make a 4th run but the Bug's factory minders said NO. Even when running poorly, a TTGT easily smokes a new Bugatti Veyron. A Bugatti rep came by my trailer to explain why the Veyron didn't run faster and to look at my GT. He couldn't seem to understand how a V-8 Ford with 2 turbos was faster than his W-16 with 4 turbos. He looked inside my car and asked me, "Is that a manual transmission?", "Do you shift that and use a clutch pedal on the floor??" He looked at that stick shift like it was a starter crank handle sticking out of the front of the radiator. I asked him if he would like to sit in it and he said NO, as he knew I was going to take his picture in a REAL performance car.

With that contest settled, there were 90 other cars at the event and one of them, the Big Red Camaro Team, had run a 217. They were spraying larger shots of Nitrous every run and told me the car dyno'd at 1400 HP. If my car was running well it would have been in the 220's and out of reach but it wasn't. So......let's make one more run and perhaps put down a 218.

At the 1/2 mile mark #34 was flying but again it struggled in 5th gear and as I approached the finish line I heard a loud 1 second rapping sound and then BOOM as an explosion shook the car and filled the engine compartment with smoke. I got on the brakes and turned at an intersection to roll up to a fire crew where I bailed out and popped the clamshell. Lots of smoke but no fire. My weekend is over. The fire crew towed my GT back to my trailer and I winched it in. Late Saturday night I called John Mihovitz and told him that I thought my new engine was toast. His first question was, "How fast did you go?" 213. "That sucks. The way I built it, it should have gone 230." His second comment was, "I don't think there is anything wrong with your motor, and if there is, it would be the first one to ever come back”. “You are 3 hours away, meet me at 10 Sunday morning at Accufab and I’ll look at it.” How about that, Sunday morning service by the man himself.

The next morning John met me with one of his techs and they spent over 2 hours bore scoping and compression testing every cylinder and looking at whatever they look at to see if it’s safe to start. “Your motor is perfect, it must be the turbos, I didn’t work on those”. Nothing like confidence ‘eh? So his tech starts the car while John stands behind it. The car is run for 3 seconds and shut down. “The right turbo has a broken shaft, your motor is fine”.
They help me load the GT back into my trailer, repaired the nylon runner under one of the trailer ramps, checked the air in the truck and trailer tires, and shot the shit for a while. Nothing that Accufab had worked on had failed and those two men spent almost 3 hours after coming in on a Sunday morning to look at my GT . What do I owe you? “Nothing, have a nice day”.

Extraordinary customer service is the norm at Accufab. They are so busy building engines (and they are the best in the business there) that they don’t normally work on cars, but they always stand behind their products. Here they turned my blown turbo into a fine morning. Thanks John! As it turns out my right turbo did have a broken shaft but both of my turbos appear to have been over spun with the blades going supersonic and self-destructing. A proper postmortem will determine their exact cause of death. It’s clear now why my TTGT was not performing. I’ll replace them and try again.

A couple years ago a great movie came out called “The Worlds Fastest Indian”. It was based on an even better book called “One Good Run” about an old man from New Zealand who worked on his ancient Indian motorcycle and took it to the Bonneville Salt Flats every year trying to put together the right combination that would produce that one good run. I know just how he felt. Cheers.

Chip
 

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ChipBeck

GT Owner
Staff member
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 13, 2006
5,783
Scottsdale, Arizona
2
 

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Howard

GT Owner
Mark IV Lifetime
Apr 26, 2007
1,150
Florida/North Jersey
Great story, Chip, with a "happy" ending. Congrats on beating the Bug.

Howard
 

Nafod

GT Owner
Mark IV Lifetime
Glad everything came out OK..# 34 is one of my favorite GT's.. Sonic pressure waves can be very destructive. We had a Supersonic Air Force fighter (FB-111) come by our carrier and the "Boom" dislodged one of the hanger bay door's.

Nice job on the VW... Priceless photo of the Bugatti tech texting back home on a iPhone there results while standing in the GT pit's...

Hope someday to start a project like your's with Accufab..

Thanks for the writeup...

Bruce
 

Indy GT

Yea, I got one...too
Mark IV Lifetime
Jan 14, 2006
2,545
Greenwood, IN
Chip, thanks for posting your interesting story.

I would be interested in hearing about the turbo postmortem. Centrifugal and axial compressor blades seldom like to be run at supersonic producing speeds. The attending shock waves produced when going transsonic or supersonic disrupts the flow which certainly leads to problems.

However, the pictures posted of the compressor inlet appear (IMO) to indicate something different. To me the mechanical blade damage pictured looks like FOD (foreign object damage). And quite extensive at that. Do you run filtered air to the inlet of your turbos? I would be especially careful to investigate the downstream piping off the turbo exit to ascertain "where" those blade chunks or the initiating FOD object wound up.

In a gas turbine, compressor blade fragments (if they do not lead to cascading rear stage failures) are usually incinerated or at least liquified by the high temperatures in the combustor and the molten blade material deposited on downstream turbine nozzles or blades. In your engine it might be wise to carefully check the upstream side of the engine intercooler for any blade pieces. You do not want to ingest these into the cylinders as than would not be "good".
 

Cobrar

GT Owner
Mark II Lifetime
Jun 24, 2006
4,025
Metro Detroit
Chip, thanks for posting your interesting story.

I would be interested in hearing about the turbo postmortem. Centrifugal and axial compressor blades seldom like to be run at supersonic producing speeds. The attending shock waves produced when going transsonic or supersonic disrupts the flow which certainly leads to problems.

However, the pictures posted of the compressor inlet appear (IMO) to indicate something different. To me the mechanical blade damage pictured looks like FOD (foreign object damage). And quite extensive at that. Do you run filtered air to the inlet of your turbos? I would be especially careful to investigate the downstream piping off the turbo exit to ascertain "where" those blade chunks or the initiating FOD object wound up.

In a gas turbine, compressor blade fragments (if they do not lead to cascading rear stage failures) are usually incinerated or at least liquified by the high temperatures in the combustor and the molten blade material deposited on downstream turbine nozzles or blades. In your engine it might be wise to carefully check the upstream side of the engine intercooler for any blade pieces. You do not want to ingest these into the cylinders as than would not be "good".

I'd be interested in the turbo postmortem as well. From the photo, the damage appears consistent with that as described by John, the engine builder - broken shaft.

Been goin' to school on those as of late... :thumbsdow Failure might be lubrication or metallurgy related. Have been looking at BorgWarner EFR series product as potential for upfit.
 

Fast Freddy

GPS'D 225 MPH
Mark II Lifetime
Aug 5, 2005
2,727
Avondale, Arizona
Chip, thanks for posting your interesting story.

I would be interested in hearing about the turbo postmortem. Centrifugal and axial compressor blades seldom like to be run at supersonic producing speeds. The attending shock waves produced when going transsonic or supersonic disrupts the flow which certainly leads to problems.

However, the pictures posted of the compressor inlet appear (IMO) to indicate something different. To me the mechanical blade damage pictured looks like FOD (foreign object damage). And quite extensive at that. Do you run filtered air to the inlet of your turbos? I would be especially careful to investigate the downstream piping off the turbo exit to ascertain "where" those blade chunks or the initiating FOD object wound up.

In a gas turbine, compressor blade fragments (if they do not lead to cascading rear stage failures) are usually incinerated or at least liquified by the high temperatures in the combustor and the molten blade material deposited on downstream turbine nozzles or blades. In your engine it might be wise to carefully check the upstream side of the engine intercooler for any blade pieces. You do not want to ingest these into the cylinders as than would not be "good".

+ 1

i had the same thing happen on my Turbocharged Kawasaki drag bike 2 years ago and the shrapnel went though the motor and i had to have my valves and rings replaced....
 

twobjshelbys

GT Owner
Jul 26, 2010
6,189
Las Vegas, NV
Veyrons are ugly. I would never let one near my daughter.

I may have asked this before - Chip what trailer do you have?
 

AJB

GT
Mark II Lifetime
Le Mans 2010 Supporter
Jun 28, 2006
2,976
Bloomfield Hills, Michigan
Chip - great story - thanks for sharing.

andy
 

Superfly

HERITAGE GT OWNER
Mark II Lifetime
Jun 23, 2008
2,210
Edmonton, Alberta
Cool story Chip. I'm well impressed with John in particular and Accufab in general. Really stand behind what they do, and it's obvious that KNOW what they do.

Interested to hear the postmortem on the turbos.
 

daytrayd

GT Owner
Mark II Lifetime
Apr 23, 2010
557
Austin, TX
I'm guessing Bugatti's PR department is on damage control trying to eliminate any mention of the GT running quickest in the upcoming C&D article, good work!

How old are your turbos btw?
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,281
It is probably too late now if the turbo(s) are out of the car - but the main suspect in a broken shaft scenario is oil starvation at the turbo main bearing and the orifice at the "fogger nozzle" should be very carefully inspected. You want to find the cause - otherwise there is a considerable risk for another failure. I would say that it is almost certainly a small foreign particle that lodged in the oil nozzle at the turbo which prevented lubrication of the bearing shaft.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,189
Las Vegas, NV
A Bugatti rep came by my trailer to explain why the Veyron didn't run faster and to look at my GT.

Chip

What was the explanation, er, excuse?
 

dbk

Admin
Staff member
Le Mans 2010 Supporter
Jul 30, 2005
15,242
Metro Detroit
It is probably too late now if the turbo(s) are out of the car - but the main suspect in a broken shaft scenario is oil starvation at the turbo main bearing and the orifice at the "fogger nozzle" should be very carefully inspected. You want to find the cause - otherwise there is a considerable risk for another failure. I would say that it is almost certainly a small foreign particle that lodged in the oil nozzle at the turbo which prevented lubrication of the bearing shaft.

x 2
 

fjpikul

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Jan 4, 2006
11,680
Belleville, IL
Good show Chipper, but don't you think it's time to paint your car RED?
 

KMCBOSS

RED GT owner
Mark II Lifetime
Dec 3, 2006
995
Bremerton, Washington
Veyrons are ugly. I would never let one near my daughter.

I may have asked this before - Chip what trailer do you have?


Looks like a Trailex
 

Mullet

FORD GT OWNER
Le Mans 2010 Supporter
Oct 21, 2008
2,468
Houston Texas
If you ain't breaking stuff you aren't driving it hard enough. :)

CHANGE YOUR SPARK PLUGS BEFORE DRIVING IT AGAIN. I change mine very often and swear by it.
 

ChipBeck

GT Owner
Staff member
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 13, 2006
5,783
Scottsdale, Arizona
The best laid plans of mice and men.....

Gentlemen,

My turbos are being sent off for analysis today and when I get the results back I'll post them. I can post what I know or think likely now based upon my conversations with people more knowledgeable than me. I'm certainly not a tech genius so I'm sure I'll have to revise something I write as I get better info. I have experienced compressor blade stall while dive testing a jet powered turboprop aircraft and it sounded like a bomb went off and shook the entire plane. A pretty violent force even though nothing but air touched those fan blades. So here's the best answers I can give right now.

I would be interested in hearing about the turbo postmortem. Centrifugal and axial compressor blades seldom like to be run at supersonic producing speeds. The attending shock waves produced when going trans-sonic or supersonic disrupts the flow which certainly leads to problems.

However, the pictures posted of the compressor inlet appear (IMO) to indicate something different. To me the mechanical blade damage pictured looks like FOD (foreign object damage). And quite extensive at that. Do you run filtered air to the inlet of your turbos? I would be especially careful to investigate the downstream piping off the turbo exit to ascertain "where" those blade chunks or the initiating FOD object wound up.

In a gas turbine, compressor blade fragments (if they do not lead to cascading rear stage failures) are usually incinerated or at least liquified by the high temperatures in the combustor and the molten blade material deposited on downstream turbine nozzles or blades. In your engine it might be wise to carefully check the upstream side of the engine inter-cooler for any blade pieces. You do not want to ingest these into the cylinders as than would not be "good".

Bill,

I thought the same thing at first but the inner volutes on both turbos are perfect and undamaged so no FOD passed through them. That combined with the most severe damage being on the outside edge of the blades (the part that was traveling fastest) and that both turbos compressor blades were damaged in the same way leads back to blade stall caused by supersonic disruption of flow. My car has K&N filters and they are undamaged and intact. The entire system upstream and downstream has been dismantled and examined and two very tiny fragments were lodged in the inter-cooler. The oil filter and magnetic plugs were examined along with the oil and it was very clean with just a few very tiny fragments found. Compression in all cylinders is perfect.

I may have asked this before - Chip what trailer do you have?

It's a Trailex. They are all aluminum, super light and easy to tow, and you can open the drivers door with the car in the trailer and get out without crawling through the window. Good stuff.

How old are your turbos btw?

They are (I guess now "were") brand new Garretts with less than 20 hours on them.

It is probably too late now if the turbo(s) are out of the car - but the main suspect in a broken shaft scenario is oil starvation at the turbo main bearing and the orifice at the "fogger nozzle" should be very carefully inspected. You want to find the cause - otherwise there is a considerable risk for another failure. I would say that it is almost certainly a small foreign particle that lodged in the oil nozzle at the turbo which prevented lubrication of the bearing shaft.

That is the first thing that was looked at on both turbos and there was nothing clogging those .020 nozzles, the lines, fittings, or the T. Both turbos look like they had insufficient lubrication however. John has considerable turbo experience and he told me that the .020 nozzle was OK for street driving but would not flow enough oil to keep the turbos happy when running all out at the Mile and that a .040 nozzle was necessary at high power levels. Only one turbo had a broken shaft but both of them were failing in the exact same way. So my question to John was, "If the turbos had too little oil wouldn't they be spinning slower because of greater friction?" His answer was, "The purpose of the restrictors feeding oil into the turbos is to feed them just enough. Too much oil around the bearings is draggy and slows them down. The minimum amount of oil that will keep them lubricated will have the least drag. So initially, as they are starved for sufficient oil they will spin faster as they pass through that sweet spot. Then friction and heat will quickly destroy them."

Because both turbos were starved in the same way and the T-fitting feeding them was not plugged either the problem was probably just undersized oil restrictors for max power Mile runs. The analysis of the turbos will reveal more when it comes back.

What was the Bugatti rep's explanation, er, excuse?

It was too hot, elevation was too high, car SHOULD have run better, and a few other things but his French accent made it hard for me to understand what he was saying. What I did understand was that he was not real happy.

Chip
 
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spyder625

GT Owner
Mark IV Lifetime
Sep 23, 2008
457
Great story and a Great ending... FORD wins again....
 

Sinovac

GT Owner
Mark II Lifetime
Jul 18, 2006
5,862
Largo, Florida
I 'm sure the Frenchman's unhappiness with your car outperforming the Bugatti broke your heart Chip.