alear

What is the reason for wanting as high of redline as possible? Is it the sound/vibration of the engine? Some performance increase?

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Jerome81

Well, my reason is that it is just a lot more fun. Nothing like a smooth, high revving engine screaming at super high revs. Makes you feel like a champ, and the sound is just heavenly. That and the fact that anybody and his dog can make an engine that can rev to 5-6K RPM, but it takes some serious engineering knowhow to make an engine rev to 8-9K RPM, be smooth doing so, and not break either. There are only a few companies out there with that kind of knowhow.

Low end grunt is nice, but the high revving engines are just way more fun.

rpm_pwr

high redline = well balanced engine = smooth feel

It also means there is a greater performance potential and has the ability to use a higher ratio differential = quick acceleration.

Oh yeah and it looks cool too

Mazda Family

With a high redline you don't have to shift as early, so you can stay in gear longer and make each gear shorter for better acceleration without lossing top speed.

spwolf

um, with a high redline, you need to shift all the time, because powerband is usually lower


Real reason for people liking high revving engines is that they are usually high output per liter engines that weight much less than V6 engines with comparable output... lots of people preffer smaller/lighter cars...

You could actually say that people like less weight in a sports car and only way you can get that from naturally aspired engine is by having high rev engine... its not the best solution really if you want to go fast

spwolf

however, its much cheaper to build light vehicle with 1.8-2.0 engine with 180-200hp than V6 with 220 hp...

F1 cars rev up to 16k-20k but have really low low torque, around 200 pounds... but its a built for track so it works great...

I would personally take Nissan's 250 HP V6 over 220 HP Type S (comparable power to weight ratio) for road use

rpm_pwr

The powerband is lower???? WTF? Cars with higher redlines often have very wide *useable* power bands and so can stay in gear much longer. For example my FD rx-7 makes solid boost from 1750rpm to 8000rpm so I can, and sometimes do, drive from 0kph to highway speeds (100kph +)all in second gear. This is very useful if you're trying to eat takeaway while driving :D

What you may be trying to say is that cars with high redlines often require a downshift when you suddenly want rapid accelaration from cruise. This is misleading and so often bullshit. Yes an S2000 feels horribly Civic like when booted from 2000rpm in fourth. But I can pull over 0.45g longitudal acceleration from 2000rpm to 7750rpm in fourth, which gives me more than enough acceleration for day-to-day purposes. I do gain about 0.1g by downshifting but I only need that for racing and only an idiot wouldnt downshift from 4th for a race anyway.

So what do I gain by having an 8000rpm redline? Well I can run a 4.11:1 diff which mean that I get more ACTUAL (not corrected) torque at the wheels than any low-revving domestic ever made here even though they have more flywheel torque. The result of this is that I have more acceleration through the power band and therefore my car is faster.

spwolf

no, what i wanted to say is that at 3k, S2000 feels like Civic... to keep it fast, you will need to keep it in narrower rpm range than if you were driving an powerful V6 or V8

now, you are arguing that it doesnt matter anyway since you dont need it to be fast all the time... why not?

based on your post, one would have to wonder why they still make V6 & V8 engines

Buger

Hmm... The thread was talking about high rpms not about the s2000. I previously posted some of the below:

The s2000 has a range of approx 2750 rpm (5750 - 8500) of 90% peak torque or greater. The vtec's first peak in the torque curve does not hit the 90% mark and the torque actually drops before slowly rising again at 4500 rpm again. This is why the s2000 has had a reputation of being "peaky".

Actually, the most amazing thing about what we have seen come out about the renesis is that it will have "90 percent of peak torque available at 3250 rpm". Assuming that the torque curve doesn't go up and down like the vtec s2000 one, this would mean that there will be 5500 rpms of 90% or greater torque in the Rx-8's powerband!!!!

Given the flat torque curve of rotary engines, would it be accurate to describe an engine with powerband of 5500 rpm with 90% or greater torque as having a "lower powerband"?

Would a driver have to "shift all the time" on such a car? Such statements are what cause others to say: WTF?

Brian

spwolf

we will not know that until we see nice hp and torque graphs...what we know now is that it will have less torque than RX-7... much less since it is naturally aspired, so having relativly small amounts of torque, even at 90% (beauty of renesis) from 3250 rpm doesnt equal to lots of torque

you can say "wtf" as much as you want, but if you are trying to compare conventional (not renesis since we dont know its details yet) vtec or vvti engine to V6, V6 (and V8 and v10 and V12) is far more superior when it comes to sheer power...

I cant believe that ppl are tyring to argue this... did you ever see super car or expensive sports car with 4 cylinder high revving vtec engine? no ;-)

Acura NSX, updated for 2002, peaks at 7100 rpm... while Toyota Celica GTS peaks at 7800 rpm, based on your assumption, is GTS a better engine somehow?

Buger

Hi Spwolf,

I believe that the assumptions here are all yours? One would think that on the rx8forum, a discussion on high rpms would not only specifically refer to piston engines where you have to shift all the time because of the narrow powerband but might also refer to the rotary which is known for its wide and flat powerband.

Alear asked why some people want a high redline, rpm_power responded with his personal experience about why he likes his car with a high redline and you ask a ridiculous rhetorical question about why v6 and v8 engines are even in existence?

It appears that you are the one assuming that nobody is aware of the advantages of having a v6 or v8.

It appears that you are the one assuming that someone (rpm_power or I?) believe that having vtec or vvti put out more power than a v6, v8, v10, or v12.

It appears that you are the one assuming that someone (rpm_power or I?) are arguing that supercars should have 4 cylinder vtecs.

It appears that you are the one assuming that someone (rpm_power or I?) think that the only criteria for a car is a higher rpm.

False assumptions, begging the question, rhetorical questions and red herrings. You try to throw everything in there when someone doesn't agree with you huh?

Brian

rpm_pwr

GM ex-buick v6 peak power 230hp (Redline 5500rpm)
90% torque lower cut-off 2000rpm
90% torque upper cut-off 4500rpm
operating range: 2500rpm

1993 JDM-only 13b-rew 230hp (redline 8000 rpm)
90% torque lower cut-off 3250rpm
90% torque upper cut-off 6750rpm
operating range: 4500rpm

call that narrow?

I'm saying that if you are within your 90% range you will have strong acceleration. read again.

hey? Not all cars are built for performance. Low revving engines are good for load hauling just not performance. Most modern high performance v6 or v8 engines have a high operating RPM range. Ever seen a ferrari motor?

-pete

rpm_pwr

You are showing the limits of your tech knowledge here. We will also need to know gear ratios and more importantly diff ratios to judge how useable the engines powerband is. Do you know why?

At risk of getting side-tracked by this rubbish - how is a single profile cam going to have more "sheer" power than a multi-stage? I cant beleive you wrote that!


Why only 4 cylinder? Plenty of performance cars are high revving - ferrari, lambo, bmw m3,m5 hell virtually all of them.

Now you've lost the plot. The argument here is that high operating RPM's can lead to a wider NOT NARROWER power band that's all Brian and I have been saying.

-pete

spwolf

well guys, putting japaneese high revvin engine together with european V6/V8 engines is hardly possible...

having 4 cyl engines that rev high brings all kind advantages is all what i was saying, but one of those advantages is not that the car is more usable...

spwolf

and I agree with Jerome81 as well ;-)

cshepley

I guess all of those 4 cylinder Lotus's of past and present don't count then.

spwolf

what are you talking about? lotus 4cyl engines are not powerful or great, well first of all they are not lotus engines (122 hp old school rover engine, brrrr)... but lotus chasis is sooo beautifully light that it doesnt matter that you dont have much power... which is what I said anyway, they are good cuz they are light, not cuz they are so powerful

cshepley

I never said the engines were Lotus engines, I referenced the cars as being lotus and that they had 4 cylinder engines. What you said earlier (and what the bulk of my reply was aimed at) was,

"I cant believe that ppl are tyring to argue this... did you ever see super car or expensive sports car with 4 cylinder high revving vtec engine? no ;-) ".

My point was there are super cars powered by 4 cylinder engines. Going further back in time you can find even more, such as several Ferrari's in the sixties. If you want to direct your search to race as well as road cars, take a look at some turbo era F1 engines, such as the race winning Brabham BMW of the 1980s.

spwolf

umm, actually super lotuses have V8 engines... cheap lotuses have 4 cyl engines ;-)

Jerome81

Actually until about 5 years ago or so, the super Lotus, the Espirit, was powered by a turbo 4 cylinder.

The Elise is also a 4 banger, probably makes about 120hp or so. Goes to 60 in about 5 seconds flat. Light weight is better

spwolf

yep, sure is... I definetly preffer lighter cars, although elise goes to extremes, I would never get it

cshepley

Try telling the owner of an S4S that they have a 'cheap' lotus and see how they respond.

spwolf

but at the same time, esprit's 4 cy turbo peaked out at 6,500 rpm, so it is hardly part for this discussion ;-))

Buger

Umm... It seems to be hard for you but let's try to understand what what a previous poster said. Are you saying that the Lotus S4S (1995 - 1996) that cshepley was talking about was not an expensive sports car?

Or were you trying to back off and change the subject by pointing out that OLDER Esprit turbos had a lower hp peak and that you didn't want anybody to talk about this anymore?

BTW, the S4S (made for 1995, 1996) that cshepley was talking about had 300 bhp @ 7000 rpm. If you want to, you can look up what the redline was for that car (7500?). Please let us know exactly what is the lowest redline that you want to discuss in this thread so we don't confuse you anymore. ;-)

Brian

spwolf

Okey, this went way too far...

4 cyl engines are my gods, no matter how high they rev or what kind of car they are in, or if they have an turbo or two... they are simply the most beautiful pieces of engineering ever made.

I submit to them...


... now, I was trying to point that reason people use "high revving engines" (which in most of other car discussions would be 4 cl engines (except for mazda's rotary), peaking above 7,000, redlining above 7,500, mostly naturally aspirated) is because they are lighter (especially) and cheaper than V6 and V8, etc, engines... I got hit by comparisons to Buick V6, Ferrari's, Espirt Turbos (Lotus has spicey version of Elise that revs actually really high, but its pretty pointless), as if I was saying that those 4-cl engines suck.. no, they dont suck, however if you want power and torque, you dont get 4 cly (even with turbos)... even Lotus knows this, thats why they finally made V8 for the Esprit.

Now we might have been sidetracked before, but there it is... it just didnt come to my mind that if some1 asks "why do people like high revving engines", they are thinking of Ferrari's or M3's