Turbo vs. NA

[///schwartzman]

C'mon guys, those numbers I try and forget... But it isn't cheap.

Why does motor swap always invariably come up in comparison to turbo builds? Is it the old adage "no replacement for displacement..." IMO the turbo niche is for those who like the S14 for what it was & is, with what it can be Once you've gone forced induction it's hard to NOT consider it a viable option on just about any car (cost independent) if VAC can pull it off it just benefits the community, hats off!

[Az in Oz]

Some good points Newera but a few that are a little off target. The original rods are remarkably robust and more than up to the task of medium levels of boost. People forget just how strong these motors really are. Forged, lower comp. pistons are a no brainer as is the clutch.
A 2.5 conversion is not neccessary at all. The 2.3 will make good horsepower. Remember these heads have quite good flow characteristics in standard trim. Force that air in and what do you think the outcome will be? One of the scariest things to deal with is the HG sealing. Have a look at the gap between cylinders 2&3 on a 2.5 and tell me what you think. If you choose to be a "horsepower slut" and go for high boost I think you'll find big issues waiting for you there.
Look at the 4 cylinder turbo market and you'll see that the majority of them are 2.0Ltrs or less.
Pumps and other components go without saying as this is something that you'd be mad not to do when embarking on any engine rebuild.

The chassis mods are a personal thing. I have choosen to upgrade all of the above to suit but depending and what you want to do with the car, these are not absolutely neccessary.

Like anything you can take this to the enth degree. I will be doing allot of the fab. and install work myself to keep $$$ down a little, we'll see where I end up

People Like Anders, Ted, Rich and Dave are the people that have real experience with this topic. We'd be well advised to listen to them on this topic.

Az

[OZM3]

I budgeted around $15000AUD for my build. I went somewhat over it but lots.

[Newera]

Sure, it's possible to cheapen it by using standard rods, rod bolts, keeping it 2.3, etc. but most people spending large sums of money on tuning will prefer faster spooling if they can get it easily with a relatively inexpensive 2.5 capacity upgrade. OZ M3's car is 2.5 - I wonder if his HG's blown?

Personally I wouldn't consider standard rods for 400 bhp + as the expense is a lot less than the consequences of a broken rod in the event of a failure...

Some good points Newera but a few that are a little off target. The original rods are remarkably robust and more than up to the task of medium levels of boost. People forget just how strong these motors really are. Forged, lower comp. pistons are a no brainer as is the clutch.
A 2.5 conversion is not neccessary at all. The 2.3 will make good horsepower. Remember these heads have quite good flow characteristics in standard trim. Force that air in and what do you think the outcome will be? One of the scariest things to deal with is the HG sealing. Have a look at the gap between cylinders 2&3 on a 2.5 and tell me what you think. If you choose to be a "horsepower slut" and go for high boost I think you'll find big issues waiting for you there.
Look at the 4 cylinder turbo market and you'll see that the majority of them are 2.0Ltrs or less.
Pumps and other components go without saying as this is something that you'd be mad not to do when embarking on any engine rebuild.

The chassis mods are a personal thing. I have choosen to upgrade all of the above to suit but depending and what you want to do with the car, these are not absolutely neccessary.

Like anything you can take this to the enth degree. I will be doing allot of the fab. and install work myself to keep $$$ down a little, we'll see where I end up

People Like Anders, Ted, Rich and Dave are the people that have real experience with this topic. We'd be well advised to listen to them on this topic.

Az

[Newera]

The chassis mods are a personal thing. I have choosen to upgrade all of the above to suit but depending and what you want to do with the car, these are not absolutely neccessary.

Az

The thought of having a 400 bhp turbo'd M3 on near standard suspension and brakes doesn't make a lot of sense to me, but each to their own, I suppose. :hee:

If anything, well chosen handling and braking improvements will make a car a lot faster (& safer) than power alone for proper hardcore driving.
Such modifications do cost a significant sum to do properly - and so I was merely pointing out they should be considered as part of the overall budget when considering a turbo conversion from a near standard M3.

[Az in Oz]

I budgeted around $15000AUD for my build. I went somewhat over it but lots.

Indeed Dave...lol
AU$ has been a bit kinder to me keeping my bottom end 2.3 has helped

Bolts are all ARP Newera, that's something not to skimp on. I'm only aiming at low to mid 300's which is achievable at around 16psi with my build specs and I'm going to run E85. Dave's car is running relatively mild boost FWIW. I'm not sure where it will end up but I'm thinking it won't surpass 21psi anytime soon... I could be wrong. I have seen first hand a 2.5 MLS HG blown through at 18psi... food for thought it was.
I have an AST 4200 coilover setup on order and a BBK... I think I've got my bases covered....

Now back to the topic on the GB kit

Aaron

[///MCon]

Wait to you hear a GT30r spooling at 7500rpm.

That Jet fighter sound is pretty sex. I just don't know what it is but I feel turbos are cheating.

[chutrain]

That Jet fighter sound is pretty sex. I just don't know what it is but I feel turbos are cheating.

How is it cheating? It's actually the best compromise for those who want the power
without having to do a swap, or spending huge sums of money to get a full blown S14
and still not put out as much power.

[Newera]

That Jet fighter sound is pretty sex. I just don't know what it is but I feel turbos are cheating.

Maybe this is going to be provocative, but what are forums for if not for discussion and examination of ideas..

An engine is a heat pump - the more air and fuel that can go through it, the more power it'll produce. The skill in tuning an N/A engine is to make it flow and pump air efficiently. A turbocharger forces air through which is considered cheating by purist tuners.

Cost aside, look at Japan's 2 currently most powerful sports cars. The GT-R and the L-FA. The GT-R a twin-turbo is hugely quick - and very impressive, but as a driver's car it's lacking soul. The LF-A makes a sound that intoxicates - ask anyone who's been in one, or been lucky enough to drive it - it's unforgetable. A credit to Toyota it's nigh on as quick as the GT-R - all with a modern N/A engine. Soul.

In 12 years of living in Japan and being involved with exporting some highly tuned cars, I've probably driven or owned almost every turbo-charged production Japanese sports car - This is not an exageration. In conclusion I'm not smitten by turbos and have gone all the way back to N/A. I've found turbos add mega wallop but lose the spirit of the engine.

After sampling all, I concluded the best turbo'd cars are rotaries - as they produce vast amounts of exhaust gas, having 6 combustion cycles per revolution. I get 430 bhp at the wheels from my well built turbo 13B engine - with not much lag to speak of - capacity is a mere 1,310cc. That's the car I chose, over 700 bhp Skyline GT-R's and such. The RX-7's the best turbocharged tunable affordable car there is, period.

But despite the RX-7's available performance my favourite driver's car is an angry N/A full tune AE86 Corolla. It's 200 bhp, revs to 9,250, eats 400 bhp GT-R's and spits them out on tight twisty mountain roads and small racetracks (Without very long straights). It's a totally involving car to drive - very hard...

There's no way a 350 bhp M3 turbo will be quicker than a well prepared RX-7 which can make 380 bhp with only basic modification and has a fantastic chassis with double wishbones (aluminium) at each corner, 50/50 distribution and light weight. RX-7's are cheap to buy - So it couldn't make sense to me to take a an appreciating E30 M3 and spend say $15K turbocharging it on the cheap and rob it of soul...when there's better cars out there to go enjoy turbos with...

I love the M3 for it's purity as a driver's car. To me the heart of the M3 has to be the sound from a full tuned N/A on a carbon airbox. This is why I for one wouldn't turbocharge mine. An N/A S14 has to be the pure way to tune an E30 M3.
It's got such a special N/A engine with so much potential to intoxicate with the sound it can make when it breathes hard, it seems a shame to lose sight of that.

[///MCon]

Maybe this is going to be provocative, but what are forums for if not for discussion and examination of ideas..

An engine is a heat pump - the more air and fuel that can go through it, the more power it'll produce. The skill in tuning an N/A engine is to make it flow and pump air efficiently. A turbocharger forces air through which is considered cheating by purist tuners.

Cost aside, look at Japan's 2 currently most powerful sports cars. The GT-R and the L-FA. The GT-R a twin-turbo is hugely quick - and very impressive, but as a driver's car it's lacking soul. The LF-A makes a sound that intoxicates - ask anyone who's been in one, or been lucky enough to drive it - it's unforgetable. A credit to Toyota it's nigh on as quick as the GT-R - all with a modern N/A engine. Soul.

In 12 years of living in Japan and being involved with exporting some highly tuned cars, I've probably driven or owned almost every turbo-charged production Japanese sports car - This is not an exageration. In conclusion I'm not smitten by turbos and have gone all the way back to N/A. I've found turbos add mega wallop but lose the spirit of the engine.

After sampling all, I concluded the best turbo'd cars are rotaries - as they produce vast amounts of exhaust gas, having 6 combustion cycles per revolution. I get 430 bhp at the wheels from my well built turbo 13B engine - with not much lag to speak of - capacity is a mere 1,310cc. That's the car I chose, over 700 bhp Skyline GT-R's and such. The RX-7's the best turbocharged tunable affordable car there is, period.

But despite the RX-7's available performance my favourite driver's car is an angry N/A full tune AE86 Corolla. It's 200 bhp, revs to 9,250, eats 400 bhp GT-R's and spits them out on tight twisty mountain roads and small racetracks (Without very long straights). It's a totally involving car to drive - very hard...

There's no way a 350 bhp M3 turbo will be quicker than a well prepared RX-7 which can make 380 bhp with only basic modification and has a fantastic chassis with double wishbones (aluminium) at each corner, 50/50 distribution and light weight. RX-7's are cheap to buy - So it couldn't make sense to me to take a an appreciating E30 M3 and spend say $15K turbocharging it on the cheap and rob it of soul...when there's better cars out there to go enjoy turbos with...

I love the M3 for it's purity as a driver's car. To me the heart of the M3 has to be the sound from a full tuned N/A on a carbon airbox. This is why I for one wouldn't turbocharge mine. An N/A S14 has to be the pure way to tune an E30 M3.
It's got such a special N/A engine with so much potential to intoxicate with the sound it can make when it breathes hard, it seems a shame to lose sight of that.

Nailed it! More power is always nice, but sometimes it just isn't the same.

[Anders]

So, have either of you guys actually driven a Turbo S14 M3? Otherwise, it's hard to put any weight to your opinions. My S14 turbo feels or sounds nothing like a Mitsu Evo, for example. I have never had more fun and enjoyed it more than I do now, and I have always loved the DTM cars.

[Ted B]

The GT-R a twin-turbo is hugely quick - and very impressive, but as a driver's car it's lacking soul.

That is a fault of the package as a whole. The fact that it is turbocharged isn't why it's a turd of a driver's car.

A smartly engineered turbo setup is one that takes everything good about a car, and amplifies it X 10. The caveat is, maybe one in every dozen or so aftermarket turbo setups I come across fits what I consider as 'smartly engineered'.

To me the heart of the M3 has to be the sound from a full tuned N/A on a carbon airbox. This is why I for one wouldn't turbocharge mine.

The carbon airbox and turbocharging are not mutually exclusive.

An N/A S14 has to be the pure way to tune an E30 M3.
It's got such a special N/A engine with so much potential to intoxicate with the sound it can make when it breathes hard, it seems a shame to lose sight of that.

The only thing to lose sight of are NA cars that quickly disappear in the rearview mirror. This is the 21st century. One can intoxicate himself with sound, or he can intoxicate himself with sound while beating the competition. I prefer the latter.

[Newera]

So, have either of you guys actually driven a Turbo S14 M3? Otherwise, it's hard to put any weight to your opinions. My S14 turbo feels or sounds nothing like a Mitsu Evo, for example. I have never had more fun and enjoyed it more than I do now, and I have always loved the DTM cars.

I know some will never agree N/A can be more fun than turbo, but my unusual experience with many turbo'd cars has taught me something I thought I'd share - as a sort of devil's advocate. If you don't believe me, then go right ahead and turbo an M3.

Granted, I haven't driven a turbo S14 - but I have driven Evo's of every model incarnation, same with Subaru GC8 & GDB models right up to a 22B. I'm not trying to show-off. Yes, Turbo performance can be very good...I'm not disputing that, but no way an uprated boost Evo engine has more soul than a tuned N/A.

Using exhaust gases to power a turbo by nature kills the N/A tuned exhaust sound and the intake sound will distinctly change as it's confined by being under pressure. No turbocharged car I've ever come across has sounded as divine as a tuned N/A in anger.

Previous JDM market only RB26 powered GT-R's are proper driver's cars & 'd be willing to bet a Skyline R32-34 GT-R makes a far more capable turbo car than an E30 M3 for a lot less money (at least outside the USA where it's possible to import such cars at lower cost... sorry it's so restricted in the states - that sucks!) I've driven countless GT-R's, from 650 bhp street spec, to full tune 900 bhp + missiles.

Such cars eat anything up they find on an open road with ease. I've arrive shaking with adrenaline after driving cars like that - but built full tune Evo, Scooby, Skyline, etc. don't have the soul of say a 115 bhp / litre N/A - which by it's very nature has to breathe it's own air efficiently.

My RX-7 is a formidable N/A. It will hang the back end on long fast 3rd gear corners and devour most cars it comes across with ease - I'll never sell it, but it doesn't ignite passion like a really well tuned N/A.

My AE86 with less than half the power sounds imensely angry and is quick enough to impress anybody that has been in it with me. It's an insanely fast little car because it's light and well sorted with an engine that thrives on revs. Some say the E30 M3 is a German take on what an AE86 is and I agree in most ways. They share broadly similar soul.

There's something to be said of having to drive 100% of an N/A car to get the most out of it than having too much power that can't be as easily employed, is hampered by reduced throttle response and has to have it's power more deftly moderated to avoid spinning into the undergrowth.

I know from my own experiences a well tuned S14 will make the hairs on the back of my neck stand erect like no turbo-charged car can on proper twisty roads. It's not about straight line power, it's about soul & purity of the drive, for me at least...

A well tuned N/A can be surprisingly capable of losing a big power turbo car on tight corners where reduced response, etc. become an achiles heel. It's huge fun in a well tuned N/A beating turbo cars with more power and ultimately more satisfying - all IMHO of course.

[OZM3]

If you don't believe me, then go right ahead and turbo an M3.

I think you'll find he already has......with much sucess.

I I know from my own experiences a well tuned S14 will make the hairs on the back of my neck stand erect like no turbo-charged car can on proper twisty roads. It's not about straight line power, it's about soul & purity of the drive, for me at least...

I'm sorry thats just a crock o shit. My car goes around the same corners even quicker now. Turbo cars are not exclusively built for the drag strip.

[Newera]

I think you'll find he already has......with much sucess.

Cool, each to their own


I'm sorry thats just a crock o shit. My car goes around the same corners even quicker now. Turbo cars are not exclusively built for the drag strip.

It's all relative, you didn't just fit a turbo'd engine - you upgraded & rebuilt the entire car.

Cool - So why didn't BMW just make a turbocharged S14's to race against Ford Sierra Cosworths back in the day...
And how many modified turbocharged E30 M3's do you know that have outstanding racing success, even nowadays?
Most race E30 M3's stay N/A because of regulations, but also because owners understand the benefits of lightened frontal weight, chassis balance and high reving engines.

I never said turbos are just for the drag strip. They can be very capable track cars too, my RX-7 is. But response and fine control of power is better from a tuned N/A than a turbo. Your M3 is one I can't help admire it's a truly awesome piece of work, but despite how impressive it may be - it still wouldn't make me want to do the same to mine. Each to their own

Soul & purity.