V8 to 8,000 RPM
Discussion
Another great drive in my 4.7 V8V yesterday. Was caught in traffic, so after an hour, I set a twisty + motorway detour to finally get home. I don’t commute in a car which means most drives are special (looking to approach 5,000 miles in the first year).
I’m really wondering what could be better following nearly a year of ownership. With regular use (nearly always journeys over 50 miles) it just gets sweeter and sweeter.
OK - I could p/x for a model with sports seats (eternal topic around here), a 700W hifi and/or other options. But these are all trinkets. The core of the car is what I’m interested in and it’s so near damn perfect. Its sublime balance really makes me hesitate about upgrading to a V12.
However... there are two fundamental design aspects which are much harder to address.
The first is the awkward position of the gear stick. It makes my upper arm ache for the next days after each spirited drive. So I could get an automated manual. Not sure if I want to sacrifice that interactivity.
The other is the rev limit of the V8. Don’t get me wrong; the current power level is more than enough. The secondary de-cat has ensured it makes progress with the best sound ever. It’s tractable and has a good reliability reputation. The dry sump also brings credibility that is sadly lacking from Merc’s crate (apparently AM were forbid from doing this so as to not upset AMG’s customers?).
So... if the sound is already glorious and epic passing 6,000 RPM, what would it be like hunting down 8,000 RPM?
My main concern would be maintaining real world useability. Keep it tractable at low RPM, maintain reliability and not dropping the MPG to sub-10!
Anybody else contemplated this? Have AM Works ever offered some such official conversion for the 4.7 engine? Bamford Rose ever offered this?
In reality it’s likeky to be more prudent to upgrade to a V12VSM, but still curious.
I’m really wondering what could be better following nearly a year of ownership. With regular use (nearly always journeys over 50 miles) it just gets sweeter and sweeter.
OK - I could p/x for a model with sports seats (eternal topic around here), a 700W hifi and/or other options. But these are all trinkets. The core of the car is what I’m interested in and it’s so near damn perfect. Its sublime balance really makes me hesitate about upgrading to a V12.
However... there are two fundamental design aspects which are much harder to address.
The first is the awkward position of the gear stick. It makes my upper arm ache for the next days after each spirited drive. So I could get an automated manual. Not sure if I want to sacrifice that interactivity.
The other is the rev limit of the V8. Don’t get me wrong; the current power level is more than enough. The secondary de-cat has ensured it makes progress with the best sound ever. It’s tractable and has a good reliability reputation. The dry sump also brings credibility that is sadly lacking from Merc’s crate (apparently AM were forbid from doing this so as to not upset AMG’s customers?).
So... if the sound is already glorious and epic passing 6,000 RPM, what would it be like hunting down 8,000 RPM?
My main concern would be maintaining real world useability. Keep it tractable at low RPM, maintain reliability and not dropping the MPG to sub-10!
Anybody else contemplated this? Have AM Works ever offered some such official conversion for the 4.7 engine? Bamford Rose ever offered this?
In reality it’s likeky to be more prudent to upgrade to a V12VSM, but still curious.
Glad you’re enjoying your car! I used to have a V8VS.
Re the gear stick position. I’m a 5ft 8” midget so I couldn’t deal with it being so far back for me.
Hence I got the V8VS with SSII. Loved it.
Then I got a V12VS with SSIII. And lightweight seats. Both perfect and absolutely essential - for me.
Personally I wouldn’t mess around with engine tuning - especially if it’s a relatively new car. Secondary decat is fine obviously. Anything internal may make it harder to sell.
Try a V12 and a V12VS first. All seat and gearbox options. But do be prepared to want one.......dust off the calculator.
Re the gear stick position. I’m a 5ft 8” midget so I couldn’t deal with it being so far back for me.
Hence I got the V8VS with SSII. Loved it.
Then I got a V12VS with SSIII. And lightweight seats. Both perfect and absolutely essential - for me.
Personally I wouldn’t mess around with engine tuning - especially if it’s a relatively new car. Secondary decat is fine obviously. Anything internal may make it harder to sell.
Try a V12 and a V12VS first. All seat and gearbox options. But do be prepared to want one.......dust off the calculator.
I have the rev limiter in my grey '07 V8V set to 7700 rpm. I did it for a couple of reasons...
First is that I almost always found myself hitting the rev limiter on track (and occasionally on the road) when trying to hold a gear between corners. It always happened just a hair too early so I knew I only needed a few hundred more RPMs to be able to use the engine how I wanted to. Since raising it to 7700 rpm, I think I've only hit the rev limiter once or twice.
Second, and slightly less important for me, is that the 4.3L gains power all the way to redline. Stands to reason that the extra RPMs bring along more power as well, so I should have a slightly higher peak HP. I don't really care about peak HP numbers but it's a nice bonus. I've heard the 4.3L heads flow better at high RPMs than the 4.7L but I don't think I've ever seen proof of that, but it's worth mentioning because I'm not sure if your 4.7L will have the same peak HP gain as my 4.3L.
Reliability isn't affected by raising the rev limiter. Reliability is affected if you find yourself using the engine in those high RPMs. There's no difference in reliability between an engine with a 7300 rpm redline and an engine with 7700 rpm if both engines are kept below 6k rpm. But an engine being run in the 7500-7700 rpm range will be worn out more quickly than one that is run in the 7000-7300 rpm range (all else being equal). Likewise, fuel efficiency is only affected by how you drive the car, not by where the engine cuts out. But yes, you'll burn more fuel running around at 7700 rpm than you will at 7000 rpm. I have a VelocityAP tune on my grey Vantage (among many, many other mods lol) and I noticed an improvement in drivability and a couple MPG increase in fuel economy during normal driving, in addition to the performance benefits.
As for whether or not you should move into a V12, that's for you to decide. I will say the money it takes to get a V8 to keep up with a V12 is considerable - mostly because of how expensive weight loss is and that's what's needed (in addition to power adders on the V8). I've driven a V12VSMR (so many letters lol) but not on track, so I don't know how well it behaves in that environment. But the V8 with some weight loss is an incredibly fun car.
First is that I almost always found myself hitting the rev limiter on track (and occasionally on the road) when trying to hold a gear between corners. It always happened just a hair too early so I knew I only needed a few hundred more RPMs to be able to use the engine how I wanted to. Since raising it to 7700 rpm, I think I've only hit the rev limiter once or twice.
Second, and slightly less important for me, is that the 4.3L gains power all the way to redline. Stands to reason that the extra RPMs bring along more power as well, so I should have a slightly higher peak HP. I don't really care about peak HP numbers but it's a nice bonus. I've heard the 4.3L heads flow better at high RPMs than the 4.7L but I don't think I've ever seen proof of that, but it's worth mentioning because I'm not sure if your 4.7L will have the same peak HP gain as my 4.3L.
Reliability isn't affected by raising the rev limiter. Reliability is affected if you find yourself using the engine in those high RPMs. There's no difference in reliability between an engine with a 7300 rpm redline and an engine with 7700 rpm if both engines are kept below 6k rpm. But an engine being run in the 7500-7700 rpm range will be worn out more quickly than one that is run in the 7000-7300 rpm range (all else being equal). Likewise, fuel efficiency is only affected by how you drive the car, not by where the engine cuts out. But yes, you'll burn more fuel running around at 7700 rpm than you will at 7000 rpm. I have a VelocityAP tune on my grey Vantage (among many, many other mods lol) and I noticed an improvement in drivability and a couple MPG increase in fuel economy during normal driving, in addition to the performance benefits.
As for whether or not you should move into a V12, that's for you to decide. I will say the money it takes to get a V8 to keep up with a V12 is considerable - mostly because of how expensive weight loss is and that's what's needed (in addition to power adders on the V8). I've driven a V12VSMR (so many letters lol) but not on track, so I don't know how well it behaves in that environment. But the V8 with some weight loss is an incredibly fun car.
Thanks for the great responses. Telum - you're right on all counts. But I wouldn't personally increase the rev limit by even 500prm without the internals being checked to be up to the job. The increase in stresses for the components involved for any additional 100prm is considerable. But if it's used on the track, it's likely worth the risk as you know what you're asking of the engine.
In all likelihood I won't do this unless it's an official solution backed by a warranty for a road car (hence why I asked AM Bristol to do the de-cat, so the warranty would stay in tact). I'm not really into modding, so it's curious that I wait for such questions to go through my head with an AM and not a Renault for Vauxhall
Other engine mods aren't really of interest to me as I'm not looking for the additional power. Simply the additional buzz! First world problems, and all that...
In all likelihood I won't do this unless it's an official solution backed by a warranty for a road car (hence why I asked AM Bristol to do the de-cat, so the warranty would stay in tact). I'm not really into modding, so it's curious that I wait for such questions to go through my head with an AM and not a Renault for Vauxhall
Other engine mods aren't really of interest to me as I'm not looking for the additional power. Simply the additional buzz! First world problems, and all that...
nickv8 said:
However... there are two fundamental design aspects which are much harder to address.
The first is the awkward position of the gear stick. It makes my upper arm ache for the next days after each spirited drive. So I could get an automated manual. Not sure if I want to sacrifice that interactivity.
I also struggled with this ergonomic issue.The first is the awkward position of the gear stick. It makes my upper arm ache for the next days after each spirited drive. So I could get an automated manual. Not sure if I want to sacrifice that interactivity.
My first drive was in a rented 4.7 with the high/thick ellbow pad - that was truly awkward to shift gears...
With my 4.3 (low/flat ellbow pad) it was better, however still not good.
So I started experimenting, re-shaped the gearknob (made me a shape-copy of the V12 Aluminium gearknob), which makes your hand sit ~15-20 mm higher - big improvement.
Then, as a last step (for now...) I bended the shifter lever slightly further forward, as decribed here:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
That moves the gearknob further forward and thus the shifting motion easier (for me).
Next step is to shorten the throw (slightly), as raising the gearknow of course elongates the throw.
Lots of effort - but in my opinion time well spent - its one of the more important things to get the ergonomics of the seating position right.
Thomas
Edited by TR-Spider on Wednesday 21st March 12:13
Very interesting mods Thomas! By just bending the gear stick, you will customise nicely with no drawbacks for (the next owner may suit as well).
I do have the standard high armrest centre, but have to admit that the cubby space is of use.
Perhaps I should try one of those pads which pops into the drink holder recess...
I do have the standard high armrest centre, but have to admit that the cubby space is of use.
Perhaps I should try one of those pads which pops into the drink holder recess...
So I just changed from 2011 V8S with BR mods , adaptive suspension,clutch & LW Fly wheel ,exhaust & power upgrade. Great car .But test drove 2015 V12SR & have to say so much better had to buy , much faster , much better ride & sportshift 3 is so much better. The V8 is still great Car
nickv8 said:
I do have the standard high armrest centre, but have to admit that the cubby space is of use.
I would strongly recommend to remove the high center armrest and go for a testdrive...BTW, the low center armrest does have a cupholder as well (let's say a bottleholder fow a small bottle, wouldn't put a cup there...)
TR-Spider said:
I would strongly recommend to remove the high center armrest and go for a testdrive...
BTW, the low center armrest does have a cupholder as well (let's say a bottleholder fow a small bottle, wouldn't put a cup there...)
Thanks for the advice. I have a long jaunt set for tomorrow, so will give it a go!BTW, the low center armrest does have a cupholder as well (let's say a bottleholder fow a small bottle, wouldn't put a cup there...)
Dal65 said:
So I just changed from 2011 V8S with BR mods , adaptive suspension,clutch & LW Fly wheel ,exhaust & power upgrade. Great car .But test drove 2015 V12SR & have to say so much better had to buy , much faster , much better ride & sportshift 3 is so much better. The V8 is still great Car
Thanks Dal. Perhaps this response is the clincher. I have one year of full AM warranty left on the V8V which gives me the time needed to save and work out the perfect car and spec. I simply need to try different cars with/out auto-manual, low centre console, 700W/B+O and of course full or 2/3 cylinder count 
Looks like my next trip to AM Bristol May be the start of a ruinous journey...
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