[Justin_Swift6]

So test drove a M4 yesterday and damn... that feels totally different than our cars and scary as hell....so every time I floored it, what I felt was relatively no power before 4k rpm and suddenly, boom, it starts to sprint forward so violently that I feel that I can’t control it(I actually freaking love that feeling), while what makes our Camaro shine is those first or second or third gear pull, when you hold the rpm anywhere between 2k-5k then floor it, the stupid strong kick, and then continue to steadily pull very strong all the way to 6k, but what you don’t feel is that uncontrollable sprint forward after 4k so I feel very confident through the beginning to the end. I also drove my friend’s Alfa Giulia Qudrifoglio before, felt basically the same as M4.
So does anyone feel the same as me? or anyone could explain what I feel? cus it doesn’t make much sense to me looking at the torque curves...

[Umbriel]

So basically you have just gotten yourself addicted to boost, an N/A car could be faster but that felling of the boost hitting and pushing you back makes it feel different.

Now want to really get addicted and really feel like it is uncontrollable? Drive or ride in a turbo V8.

[RyanR623]

I had a Supra Turbo, and i'll take power on demand (not just over 3k RPM) over that slingshot feeling. I hated that turbo lag, but all hell did break loose at over 3500rpm. I had an aftermarket turbo, full 3" downpipe and exhaust, electronic boost controller and a fuel management system to name a few. It ripped, but also blew headgaskets (even the metal ones), quite often.

So it was fun, but i prefer torque on demand, and the push you into the seat right from the get go. Once used car values come back down i'll likely try to find a ZL1.

[UnknownJinX]

I recall watching the Regular Car Review's take on the Cadillac ATS-V. Supposedly the LF4 can feel like that, too. Doesn't come alive until 5k RPM according to the video.

In hindsight, I should have given the ATS-V a chance but the predictability and the sound of an NA V8 is just too appealing. That's especially considering the M4's S55 weedwhacker exhaust... It's just baffling how it sounds worse than the N55(which I tried in a buddy's 435i w/M Package).

[Umbriel]

Originally Posted by RyanR623

I had a Supra Turbo, and i'll take power on demand (not just over 3k RPM) over that slingshot feeling. I hated that turbo lag, but all hell did break loose at over 3500rpm. I had an aftermarket turbo, full 3" downpipe and exhaust, electronic boost controller and a fuel management system to name a few. It ripped, but also blew headgaskets (even the metal ones), quite often.

So it was fun, but i prefer torque on demand, and the push you into the seat right from the get go. Once used car values come back down i'll likely try to find a ZL1.

That's why I said a turbo V8, I had a 1000 HP turbo 4th gen and it had power down low and then had that slingshot on top, a lot more fun I'm sure than a 6 cylinder set up like that.

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[BluinSC]

Originally Posted by Umbriel

That's why I said a turbo V8, I had a 1000 HP turbo 4th gen and it had power down low and then had that slingshot on top, a lot more fun I'm sure than a 6 cylinder set up like that.

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Or if you want something more modern. Any Merc AMG

[HDRDTD]

The turbo lag you felt in the M4 is precisely the feature/problem with the early Porsche 911 turbos and made them tricky to drive hard.

[Drags1998]

I Traded a V12 Twin Turbo Mercedes SL 600 for My Camaro, Do I Miss the Power and Torque, Hell Yeah, But I sure DON'T Miss the COST of REPAIRS!!!!!The Smoothness and power of that Car will NEVER be matched By any V8.

[JamesNoBrakes]

This does not sound right. There are differences with throttle mapping and gear shifts depending on the selected drive mode on the BMW, but they make full torque around 1700 or so. There's no "sudden boost" at 4K, that's an old-school laggy turbo way downstream from the exhaust and everything about the M4's engine is designed to not have this, it's massive (full) torque at virtually any RPM.

What I would experience more than anything in my turbo BMW was just throttle lag and the engine naturally downshifting for more power and none of those was turbo lag. That one built full boost even slightly lower. Basic point is what you're describing isn't turbo lag. On my WRX...that was turbo lag, had to get it up to about 2500 before it started getting on the positive side of things and at about 2800-3000, BOOM, it just took off like a rocket. If you put it in a gear below 2500 and throttled it under load (tried to accelerate) the opposite would happen, it would just get slower.


If that BMW IS taking to 4000 rpm to go to full boost, it's broken.

[Justin_Swift6]

Thank you guys for the replies, I should definitely drive a c63 to feel that twin turbo v8!
However I don't think the M4 was broken cus I experienced the exact same thing in the alfa quadrifoglio, that one even needed to get to 5k to feel that slingshot. However I drove the M4 very briefly, like 10 mins and all the pulls were WOT, I didn't have a chance to apply partial throttle to feel those low down torque, all I know is when I pressed the gas, it would downshift and start from like 3k rpm and I don't really feel it until 4k+. Same story for the Alfa, I drove it on a roadcourse so all WOT.
I guess since turbo uses exhaust gas, when I applied full throttle and it started from 3k, even it should already make peak torque, but there was no much exhaust gas, and then during the process of going from 3k to 4k the engine produced enough exhaust gas so it started rocketing at 4k?
Another thing that leads me to this thought is whenever we hold our Camaro at 2nd gear at anywhere between 2k-5k and floor it, we will feel a very strong INSTANEOUS kick right? That's not the case for the M4 and Alfa, even when I hold them at 4k or 5k rpm and floor the gas, they still need some time (at least go up another 0.5-1k rpm) to really start pulling, no instaneous kick at all. In other words, our cars will kick at a certain rpm, but those twin turbo makes power by the process of revving up.
It's only my own theory based on what I felt when doing WOT pulls, I could be totally wrong, any correction and opinion is welcome

[UnknownJinX]

I have tried a buddy's RS7. Mad stuff.

The thing is that in Eco mode, there is a ton of lag when you floor it. When you turn on Dynamic mode, however... That thing is a beast, grips very well thanks to Quattro, and crackles like nobody's business.

What mode are you in when you drove the M4? Might have made a difference in these turbocharged cars as a more aggressive shifting mode would have kept the RPM high for longer before upshifting, which would give you more boost on demand.

Sent from toaster or something

[JamesNoBrakes]

Originally Posted by Justin_Swift6

Thank you guys for the replies, I should definitely drive a c63 to feel that twin turbo v8!
However I don't think the M4 was broken cus I experienced the exact same thing in the alfa quadrifoglio, that one even needed to get to 5k to feel that slingshot. However I drove the M4 very briefly, like 10 mins and all the pulls were WOT, I didn't have a chance to apply partial throttle to feel those low down torque, all I know is when I pressed the gas, it would downshift and start from like 3k rpm and I don't really feel it until 4k+. Same story for the Alfa, I drove it on a roadcourse so all WOT.
I guess since turbo uses exhaust gas, when I applied full throttle and it started from 3k, even it should already make peak torque, but there was no much exhaust gas, and then during the process of going from 3k to 4k the engine produced enough exhaust gas so it started rocketing at 4k?
Another thing that leads me to this thought is whenever we hold our Camaro at 2nd gear at anywhere between 2k-5k and floor it, we will feel a very strong INSTANEOUS kick right? That's not the case for the M4 and Alfa, even when I hold them at 4k or 5k rpm and floor the gas, they still need some time (at least go up another 0.5-1k rpm) to really start pulling, no instaneous kick at all. In other words, our cars will kick at a certain rpm, but those twin turbo makes power by the process of revving up.
It's only my own theory based on what I felt when doing WOT pulls, I could be totally wrong, any correction and opinion is welcome

The only way to do this is IMO in manual-mode (or with a true manual) where you can hold it in gear. Otherwise, those downshifts are screwing with stuff. You won't necessarily go as fast by holding it in gear, but you'll get a better idea of the torque and how it builds/is flat. Usually, these cars go for high gears and when you mash the pedal, it has to downshift a few gears, it'll sometimes be a little confused whether it should do one or two, then it'll pop down and the RPM will go high and all of a sudden you are going like you got hit in the rear, probably at the peak torque, but again, these cars tend to make pretty massive torque below the curve, even at lower RPM. It's lag, but not turbo-lag. The SS and M4 were about the exact same as far as lap times. The 1LE is a little better due to the chassis and suspension and chassis for chassis, the 1LE is better, but then again it's more optimized as a performance chassis, where the M4 is borrowed from the 3-series. The more true competitor performance-wise is the M4 GTS, but the price is stratospheric and the trade-offs extreme (no door handles, stripped interior, etc.). Mainly, the alpha 1LE is a better chassis and it shows.'

If you want to do a study in turbo lag, look at something like an STI vs a BMW N20/26. The STI has to wrap both exhaust manifolds around the engine on opposite sides, and then meet, at which point you have the turbo, but it ends up being a "long ways" from the exhaust heads and due to this, they lose heat and exhaust velocity. The intake piping is somewhat important, but not "as" important, unless you are trying to fill too large of a volume (tuners will sometimes put bigger intercoolers on there without doing anything else). In general, making more power with a bigger turbo is not terribly hard, but it usually raises the RPM required to build significant boost, so going to a much larger turbo like a GT35 or such can mean 4000+ to really get to the boost. This is when you get into real crappy lag, but the stock STI is archaic by modern standards, so it's lagging to around 3000rpm due to all of that piping and lag. My WRX spooled faster, due to a smaller turbo. Going to something like the N20/26, or really any modern setup, the turbo is a small twin-scroll, tapping directly off the exhaust. Often, the exhaust header is a one-piece unit containing the turbo. It's simply "right there" next to the block and cylinders, there's no significant lag, exhaust remains hot and has plenty of velocity. Small turbos spin up fast. Twin-scroll makes it work even better at lower RPM. The tradeoff is usually "running out of steam" at a lower RPM, in that full torque is realized earlier and after 5K or more, it's flat and starts to decrease. But when de-rating, you can usually get some pretty nice flat torque "curves" with these setups. Tuners will tweak the profile to get more boost, but it'll run out of steam faster when they do this, providing more peak, but falling off more rapidly (out of breath) as RPM increases. We're seeing more radical setups these days, such as electric-turbos or hybrid-assist to provide more torque at low RPM before the turbo reaches full torque, even though we are talking low RPM like 1000. If you look at the torque/rpm of BMWs like the 335s, 340s, 550s, M5s, and all of that, you'll see tons of torque at low RPM. The M5 V8 nests the turbos in between the "V" for the same reasons explained above, to keep the exhaust hot and extract maximum energy and spin them up as fast as possible. While there is a *slight* delay when you hit full throttle, where the turbo has to react to the exhaust gas, this is so slight that most people aren't really trained to notice it. Like a fraction of a second. The same effect when I take my WRX and rev match from 5th into 3rd on the hiway and floor it. I'm already in the "boost-range" going to 3.5K in 3rd and it goes "nearly instantly", but there's just a tiny bit of lag there as the pressure builds. It's hard to impress how "fast" this is, it's not the "killer lag" that all of a sudden kicks the car in the rear like the first Porsche Turbo 911 "widow maker", that's the 3000-4000rpm thing when you hit it moving through that RPM and it just starts taking off exponentially faster. The lag to build power when you are already in the boost range is very very short, as you hit the gas and the turbos almost instantly respond. There's a big difference between the modern turbo cars, and the "old" ones, like the old 911 turbo and the present day STI. The old 911 and current STI exhibit some pretty serious lag, but this is not the case with all turbo cars and *most* manufacturers have designed this out of their turbo cars. What is usually being felt is the transmission downshifting and the time it takes to do this, combined with less aggressive throttle mapping.

The biggest problem though with these modern BMW and german sedans IMO is how they are just not going to hold up over the long haul. They are so highly strung with twin turbos and massive HP packed into the package that more than a few years and you need to dump the car to avoid catastrophic failures, like engine, trans, etc. The higher strung (M5, etc.), the worse it is. These live on their leases and the owners that know simply lease for a few years and are done. This is becoming a wider problem, not just german cars, but this is probably where it's most extreme. One day, half of my ****ing BMW didn't work, the rear half. For whatever reason, the rear computer decided to just quit, so rear hatch dead, rear lights dead, basically any electronics aft of the front seats, dead. Had to get it re-programmed and at the time it was under warranty...but WTF? What if it wasn't? What about years down the road? Our Camaros are not immune from this, but at least more controlled due to a bit simpler (not much though) and cheaper. I won't rule out another german car, but I sure as hell won't hold on to it.

[Jsreo]

Originally Posted by JamesNoBrakes

This does not sound right. There are differences with throttle mapping and gear shifts depending on the selected drive mode on the BMW, but they make full torque around 1700 or so. There's no "sudden boost" at 4K, that's an old-school laggy turbo way downstream from the exhaust and everything about the M4's engine is designed to not have this, it's massive (full) torque at virtually any RPM.

What I would experience more than anything in my turbo BMW was just throttle lag and the engine naturally downshifting for more power and none of those was turbo lag. That one built full boost even slightly lower. Basic point is what you're describing isn't turbo lag. On my WRX...that was turbo lag, had to get it up to about 2500 before it started getting on the positive side of things and at about 2800-3000, BOOM, it just took off like a rocket. If you put it in a gear below 2500 and throttled it under load (tried to accelerate) the opposite would happen, it would just get slower.


If that BMW IS taking to 4000 rpm to go to full boost, it's broken.

I agree with this, I did the 2 day BMW performance school a few years ago and got to drive a number of different M2’s, M3’s, & M4’s on a track for many hours.

The boost came on well below 4K rpm in all of them

[Fraxum]

Originally Posted by Umbriel

So basically you have just gotten yourself addicted to boost, an N/A car could be faster but that felling of the boost hitting and pushing you back makes it feel different.

Now want to really get addicted and really feel like it is uncontrollable? Drive or ride in a turbo V8.

Yea, my friend borrowed my TT Gen5 1LE and flipped it over at Millville. He was fine, the 1LE not so much. A 200 RWHP 4K RPM surge is not good to use in a corner.

I have had 2 supercharged and 1 TT modern Camaros including a TT 3 series. I find out after all those cars I prefer good old NA cubic inch predictable torque over high rpm power. It is so much more relaxing on a long drive enjoying the power now and then.