The Quest for 600 bhp - Part 1 - Introduction.
Discussion
AN INTRODUCTION TO THE QUEST.
I have decided that the E31 has a lot of potential stored away in that 2 tonne shell that is just waiting to be released.
(A little like that AC/DC track "Whole lotta Rosie" I play at full volume on track days!)
300 bhp from 5.0l or even 380 bhp from 5.6l is really not that impressive.
With modern, multi-valvers making over 100 bhp/litre normally aspirated for at least 10 years now (BMW M3), our poor old SOHC 2-Valvers are showing their age. With a big old 2 tonne @rse to haul along, it's time we either went on a diet, or made some horsepower.
Losing a tonne or so would help, but unless we fit the motor in a Go-Kart or Mini-Moto, this is unlikely to happen, so we need to make some horsepower.
Cylinder head design excludes he normal route of capacity/ headwork/ cams and exhausts etc getting anywhere near major horsepower gains although some have been very impressive and demand full attention, such as Faisals superb 6.0l conversion with additional mods and Steve Cohen's similarly impressive 6.0l. I have a HUGE respect for the achievments of both of these cars, and make the comparison of these with a £5000 Hi-Fi vinyl turntable, the epitome of engineering excellence and an engineering "work of art".
BUT I NEED MORE.
The superb twin-turbo conversions of Dinan, John in DC, Allan Delisser and others have proven that the route to 100 bhp/litre with these motors is through forced induction, and in all these cases, turbo-charging. With these motors making upwards of 500 bhp RELIABLY, I decided to begin a quest to design, engineer and build a forced induction motor with the aim of achieving 600 bhp, exactly the specific bhp/litre of an E46 M3. I honestly believe I could achieve 1000 bhp from the V12, ( I already made 305 bhp from 1170cc), but want to engineer a streetable, road mannered engine with stock maintenance and reliability. As I cannot honestly engineer and design something from scratch that has already been done numerous times, and all the answers to any questions are already there, and I have a fair bit of experience with designing turbo kits anyway, I decided to SUPERCHARGE the car.
Now this is also not new, but with little or no details, a few odd pictures but with no specifics, and the only production one ever being the Koenig, it gave me the opportunity to build a project car from the design board to the dyno.
I will be posting a series of articles from work I have already done over the last few months, to work as it is carried out on the car. I will give details of the why's and wherefore's as the quest advances but very specific details will not be divulged until I am happy that the designs and engineering is correct. I will try and do regular updates but I do not always have time to do so.
Should anyone have any questions or queries on any details please feel free to ask ON the forum for ALL to share and I will try and answer all questions, time permitting.
THE QUEST - To get 600 bhp with stock reliability and driveability
THE CAR - A 1996 850CSi
WHY THIS CAR? - It's high compression and difficult to supercharge, anything else is too easy!
THE METHOD - Supercharging
THE RULES - Pump fuel, stock engine components, emissions compliant,
ALLOWABLES - Uprated clutch/flywheel, cooling system upgrades, relocation of components,
Articles to follow will (probably) be,
Fuel system, Cooling system, superchargers selection, intercooling, supercharger drive, exhaust system, transmission, and anything else that may be of interest.
Please let me know if you want me to continue posting on this project as it progresses. Thanks.
Big apologies to the 840 owners, this is for the V12's only, you guys can just buy kits anyway! he he.
8Tech.
I have decided that the E31 has a lot of potential stored away in that 2 tonne shell that is just waiting to be released.
(A little like that AC/DC track "Whole lotta Rosie" I play at full volume on track days!)
300 bhp from 5.0l or even 380 bhp from 5.6l is really not that impressive.
With modern, multi-valvers making over 100 bhp/litre normally aspirated for at least 10 years now (BMW M3), our poor old SOHC 2-Valvers are showing their age. With a big old 2 tonne @rse to haul along, it's time we either went on a diet, or made some horsepower.
Losing a tonne or so would help, but unless we fit the motor in a Go-Kart or Mini-Moto, this is unlikely to happen, so we need to make some horsepower.
Cylinder head design excludes he normal route of capacity/ headwork/ cams and exhausts etc getting anywhere near major horsepower gains although some have been very impressive and demand full attention, such as Faisals superb 6.0l conversion with additional mods and Steve Cohen's similarly impressive 6.0l. I have a HUGE respect for the achievments of both of these cars, and make the comparison of these with a £5000 Hi-Fi vinyl turntable, the epitome of engineering excellence and an engineering "work of art".
BUT I NEED MORE.
The superb twin-turbo conversions of Dinan, John in DC, Allan Delisser and others have proven that the route to 100 bhp/litre with these motors is through forced induction, and in all these cases, turbo-charging. With these motors making upwards of 500 bhp RELIABLY, I decided to begin a quest to design, engineer and build a forced induction motor with the aim of achieving 600 bhp, exactly the specific bhp/litre of an E46 M3. I honestly believe I could achieve 1000 bhp from the V12, ( I already made 305 bhp from 1170cc), but want to engineer a streetable, road mannered engine with stock maintenance and reliability. As I cannot honestly engineer and design something from scratch that has already been done numerous times, and all the answers to any questions are already there, and I have a fair bit of experience with designing turbo kits anyway, I decided to SUPERCHARGE the car.
Now this is also not new, but with little or no details, a few odd pictures but with no specifics, and the only production one ever being the Koenig, it gave me the opportunity to build a project car from the design board to the dyno.
I will be posting a series of articles from work I have already done over the last few months, to work as it is carried out on the car. I will give details of the why's and wherefore's as the quest advances but very specific details will not be divulged until I am happy that the designs and engineering is correct. I will try and do regular updates but I do not always have time to do so.
Should anyone have any questions or queries on any details please feel free to ask ON the forum for ALL to share and I will try and answer all questions, time permitting.
THE QUEST - To get 600 bhp with stock reliability and driveability
THE CAR - A 1996 850CSi
WHY THIS CAR? - It's high compression and difficult to supercharge, anything else is too easy!
THE METHOD - Supercharging
THE RULES - Pump fuel, stock engine components, emissions compliant,
ALLOWABLES - Uprated clutch/flywheel, cooling system upgrades, relocation of components,
Articles to follow will (probably) be,
Fuel system, Cooling system, superchargers selection, intercooling, supercharger drive, exhaust system, transmission, and anything else that may be of interest.
Please let me know if you want me to continue posting on this project as it progresses. Thanks.
Big apologies to the 840 owners, this is for the V12's only, you guys can just buy kits anyway! he he.
8Tech.
Sounds like the start of a fascinating tale, well done that man! 
I few ideas have gone through my head in the dark hours:
1. Remove rear seats
2. Replace monstrously heavy front seats with light-weight buckets
3. Remove all inner door linings
Conservative estimate c. 250kg?
However, after a week or so of possession I've come to some other conclusions:
1. 380bhp and 405lb/ft are quite enough for me at the moment (I'm obviously a girl's blouse).
2. These care are so rare now (say 75 rhd in existence) its almost a shame to start messing with them????
Best of luck, keep us posted!
I few ideas have gone through my head in the dark hours:
1. Remove rear seats
2. Replace monstrously heavy front seats with light-weight buckets
3. Remove all inner door linings
Conservative estimate c. 250kg?
However, after a week or so of possession I've come to some other conclusions:
1. 380bhp and 405lb/ft are quite enough for me at the moment (I'm obviously a girl's blouse).
2. These care are so rare now (say 75 rhd in existence) its almost a shame to start messing with them????
Best of luck, keep us posted!
If you continue to keep the stock high compression ratio you're already at a disadvantage.
You'll end up retarding the ignition so much to avoid detonation that you'll throw away good torque for a given level of boost. You may even burn the exhuast valves heads off due to excessive exhaust valve temps. You would have had much more torque if you lowered the CR.
You would have to therefore limit the level of boost to stop these mentioned problems, and this is counter productive to producing 600 Bhp.
The other way is to change the cam timing to lower the effective CR but you'll be working the boosting system to very very high pressure ratios where the efficiency will be poor and again, counter productive to your 600 Bhp target.
You'll end up retarding the ignition so much to avoid detonation that you'll throw away good torque for a given level of boost. You may even burn the exhuast valves heads off due to excessive exhaust valve temps. You would have had much more torque if you lowered the CR.
You would have to therefore limit the level of boost to stop these mentioned problems, and this is counter productive to producing 600 Bhp.
The other way is to change the cam timing to lower the effective CR but you'll be working the boosting system to very very high pressure ratios where the efficiency will be poor and again, counter productive to your 600 Bhp target.
Talkwrench said:
Hi Gerry! Its UK_Mike in my Talkwrench guise.
Welcome to Pistonheads. I haven't noticed you here before.
We've recently been drumming up a fair amount of interest in the 8's. At long last people are realising what a brilliant car they are......
^^^^ and he's the guy that's rebuilding my Ci at the moment Welcome to Pistonheads. I haven't noticed you here before.
We've recently been drumming up a fair amount of interest in the 8's. At long last people are realising what a brilliant car they are......
He's said a lot of good things about you Gerry and we have discussed supercharging mine at some point in the future with specific reference to your endeavours ... so yes, I'm interested
Talkwrench said:
Hi Gerry! Its UK_Mike in my Talkwrench guise.
Welcome to Pistonheads. I haven't noticed you here before.
We've recently been drumming up a fair amount of interest in the 8's. At long last people are realising what a brilliant car they are......
I thought I would look in to the forum and see what it was about. QUITE PLEASED TO SEE A FEW 8 RELATED ARTICLES SO i THOUGHT i MIGHT JOIN UP AND MAKE THE ODD CONTRIBUTION WHERE POSSIBLE.Welcome to Pistonheads. I haven't noticed you here before.
We've recently been drumming up a fair amount of interest in the 8's. At long last people are realising what a brilliant car they are......
Good to see you here Mike.
8Tech.
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