Feel of HP & Torque

[fhptom]

I was out driving my Titan the other day and had to get over 2 lanes of traffic so I nailed it to get past a few other cars.The feel of pushing me back in the seat was nice. I am trying to get that feeling in my 260 track car and my next move is completing my stroker. Just wondering if anyone has replicated that feeling with a N/A L-6 motor. I know my Titan has 300+ hp but it also weighs a ton... You LS & turbo guys get that feeling easily. A N/A built car can get around the track quickly but that is helped with other mods we do to our cars.

 

My Mustang and Camaro patrol cars gave me that feeling but again they are big V-8s.

 

Can I get that feeling again with my L-6 without giving Rebello or someone else 5-10K?

 

Tom

[JMortensen]

Your Titan does 0-60 in about 7.5 seconds. I get the same impression of power in my GMC Sierra which has 315 hp and does 0-60 in 8.5 seconds. I think if you really want that feeling of being pushed back in the seat, the solution is sloppy, softly sprung suspension and a big cushy seat. I drove a 911 Turbo that was modded and had 550 hp. The feeling was different. It didn't lay back like my truck does and give me the impression of a large mass accelerating, but I could feel my head pushing into the headrest on the seat under WOT. If you had an accelerometer you could really measure the acceleration and prove my point, but I think it's a pretty safe guess that your car is faster than your truck and that the feeling comes from something other than the g forces during acceleration.

 

If your car isn't faster than your truck then I suggest a long look at the stickies in the L6 forum. I think you can get most of the hp of a Rebello build in your garage if you take the time and study the threads and books like How to Modify, and then do your best imitation of that, provided you have some skill and mechanical aptitude.

[BRAAP]

Jon summed it up really well.

 

 

My input is if you are looking for significant torque increase that will make you grin, (torque is what gives that sit-back feeling in your seat), then your options are, in no particular order;

 

1) Turbo

2) Nitrous

3) Supercharger

4) Displacement, (usually in the form of a different engine, V-8 etc).

5) Car/you on a serious diet to shed at least 10% overall combined driver/car weight, the more

6) $5k+to Rebello or yourself mimicking a high end L-6 build that will be maxxed out where the above are just starting.

 

There are numerous little things you can do or have done that help increase torque output over stock, but for N/A the gains are gonna be small and only slightly noticeable. Little things such as mild DIY porting in the head, header and exhaust, upgrade the ignition system, lighten flywheel, and most important step, fine tune. Not just ideal ignition timing and fuel mixtures, but parts combinations and assembly of those parts.

 

A slight gain is sometimes nice, but most often not enough or just a tease when what you really want as moderate torque increase that puts a smile on your face every time you mash the loud pedal. Then see the list of 6 options above.

 

Keep in mind, how that torque is delivered has a very strong affect on the perception of power, as Jon's stated with the Porsche and pickup scenario. Flat torque curves are great, but boring, Torque the peaks quickly and falls off will smoke the tires well but runs like a tractor. Torque that starts mild and continues build as the RPMs increase, even though it may only be less overall torque then other two scenarios, will "feel" incredibly fun.

[T-Bone028]

Please correct me if I'm wrong, but aside from increasing power, have you considered changing your differential to something like a 3.7 or 3.9 to help with that "feeling" of acceleration?

[johnc]

Please correct me if I'm wrong, but aside from increasing power, have you considered changing your differential to something like a 3.7 or 3.9 to help with that "feeling" of acceleration?

 

Exactly, its not just engine torque, its the torque at the wheels. 4.62 gears, 275 ft. lbs. in my old 2,100 lb. NA race car pushed me and my passengers back in the seat very well from 4,000 to 7,500 rpms.

 

I think the "feeling" of torque has more to do with how immediate that feeling is then the actual push-back. Again, using my old race car as an example, accelerating from 3,000 on up felt more gradual then from 5,000 on up. At 5,000 rpm the reaction to the throttle was instant, at 3,000 rpm there was a much softer reaction until the car came on the cam at 4,200.

[z-ya]

I Think the seat of the pants feel has more to do with power:weight ratio than anything else. My Silverado pulls pretty good for a 5000lb vehicle, but my NA track car (180WHP) weighing 2100lbs feels a lot better. But lets face it, any reference to "feel" in power estimation is pointless IMO (unless you somehow had your butt calibrated for horsepower measurement ). Vehicles with different power:weight ratios are going to feel much different regardless of of how much absolute power is produced. Compare a 100HP sport bike to a 400HP truck, the sport bike will pull much harder making 1/4 the power.

 

I suggest you get it on a dyno and MEASURE it before and after the stroker!

 

Pete

[BRAAP]

Please correct me if I'm wrong, but aside from increasing power, have you considered changing your differential to something like a 3.7 or 3.9 to help with that "feeling" of acceleration?

 

 

 

Deeper butt gears will put more torque to the wheels, at the expense of spending less time in each gear, It's all relative.

Personally I prefer to remain in each gear as long as possible and experience as much of that feeling of torque as possible, not rowing through 2-3 gears getting a brief kick in the pants in each gear.

My V8 280-Z was a great example. 3.90 butt gears with welded spiders, (obnoxious for the street). World Class T-5 with 2.9x first gear and 1.9x second gear. 1st gear was literally useless under any circumstance. 2nd gear was the launch gear at the strip and also the take off gear when just tooling around town, even taking off on a small hill with grandma in the car. There was enough torque on hand at idle that the car would take off in 2nd gear just as mundane as the L-6 did in 1st gear, no fuss, no riding the clutch to coax it, it just did it, and 2nd gear took the car through 55 MPH! From 0 to 55 MPH in one gear with enough torque on tap at that you could “not” hold the pedal to the floor at any point in that gear without spinning the tires,. Even third gear would break the tires loose on the freeway as it passed through torque peak, (scares the crap out of passengers when that happens. Definitely could've used a taller diff with 2nd gear as the launch gear). I much prefer this scenario vs one that is just as quick to 55 or even 105 MPH or pulls just as hard but has to use twice as many gears to get the same speed, but it also requires having more torque available from the engine in the first place. But that is just me.

[johnc]

Deeper butt gears will put more torque to the wheels, at the expense of spending less time in each gear, It's all relative.

Personally I prefer to remain in each gear as long as possible and experience as much of that feeling of torque as possible, not rowing through 2-3 gears getting a brief kick in the pants in each gear.

My V8 280-Z was a great example. 3.90 butt gears with welded spiders, (obnoxious for the street). World Class T-5 with 2.9x first gear and 1.9x second gear. 1st gear was literally useless under any circumstance. 2nd gear was the launch gear at the strip and also the take off gear when just tooling around town, even taking off on a small hill with grandma in the car. There was enough torque on hand at idle that the car would take off in 2nd gear just as mundane as the L-6 did in 1st gear, no fuss, no riding the clutch to coax it, it just did it, and 2nd gear took the car through 55 MPH! From 0 to 55 MPH in one gear with enough torque on tap at that you could “not” hold the pedal to the floor at any point in that gear without spinning the tires,. Even third gear would break the tires loose on the freeway as it passed through torque peak, (scares the crap out of passengers when that happens. Definitely could've used a taller diff with 2nd gear as the launch gear). I much prefer this scenario vs one that is just as quick to 55 or even 105 MPH or pulls just as hard but has to use twice as many gears to get the same speed, but it also requires having more torque available from the engine in the first place. But that is just me.

 

Or, better yet, a 2.2 first gear, 1.8 second gear, 1.4 third gear, 1.0 fourth gear, and .80 fifth gear.

[T-Bone028]

Absolutely, I agree its all relative. There are trade-off's.

 

But sometimes, after exhausting a a majority of options with a relatively budget minded NA L6 build (which I assume is what fhptom is shooting for), gearing swaps can give that little seat of that pants kick some of us are looking for.

 

For me, I do not feel that my car is fast, but instead "quick".

[kelltainer]

I think if you really want that feeling of being pushed back in the seat, the solution is sloppy, softly sprung suspension and a big cushy seat.

 

 

I dont know about this.....my dads c5 puts me in the back of my seat no problems at all! 375torque and 310whp convertible and i am thrown in the back of my seat very easily..... A durango with the 6.0?(the one that came with the bigger engine than the 5.4) didnt put me in the back of seat like the vet did, or my buddies rx-7. I think a lot of it depends on the person as well as the gearing, its the whole "tomato, tomatO" thing.

[JMortensen]

I dont know about this.....my dads c5 puts me in the back of my seat no problems at all! 375torque and 310whp convertible and i am thrown in the back of my seat very easily..... A durango with the 6.0?(the one that came with the bigger engine than the 5.4) didnt put me in the back of seat like the vet did, or my buddies rx-7. I think a lot of it depends on the person as well as the gearing, its the whole "tomato, tomatO" thing.

 

Let me be more specific:

 

I think if you really want that feeling of being pushed back in the seat with a low power to weight ratio, the solution is sloppy, softly sprung suspension and a big cushy seat.

[Tony D]

Oh, we got sooooo close, I think Braap got the closest saying 'lower gears in the butt'---what we are talking about here is a butt-dyno feeling. Everyone worked around it, but in the end it's subjective and most of the time dreadfully wrong.

 

My classic example was a Fairlady Z I picked up which had 40mm DCOE Webers, a Header, loud exhaust, worn shocks out back with stock springs. Car felt fast as heck! I mean, back end squatting (who said soft springs?), real 'snap your head back launches'. Made all the right sensory stimulations to feel quicker than quick.

 

When dynoed it had (gasp) 86 RWHP. It's 1/4 mile time was in the high 16, low 17 second range. Sounded great, everybody who was in it thought it was pretty snappy.

 

Pulled all the go-fast goodies off it, replaced the stock EFI, did basic cleanup and the car felt slower. It was now dynoing at 147HP, wasn't running pig rich, wasn't loud with the extra muffler installed in the tranny tunnel, but dropped it's 1/4 mile times to consistent 15.50's---a solid second + faster in the 1/4 mile. But with the new Tokikos in the back, it didn't feel faster than it did before!

 

I think the best answer was to put a G-Tech or some such device in it, and actually see what your car is doing as opposed to [/i]feeling[/i] it.

 

In the world of performance, the highly subjective butt-dyno is very misleading. Having a turbo car that starts slipping the wheels when you romp on it at 65mph in 3rd gear actually feels like it's falling on it's face...until you see the haze in the rearview mirror. When it catches...lookout!

 

Low gears, soft suspension settings, and a bump in torque somewhat will give the impression of speed without actually going fast. For everyone who rode in the car and drove it, to a man every single one thought I had 'tamed it down' after the EFI and mods to the springs/shocks out back. The dyno (and actual dyno, not the Butt Dyno) and track times said otherwise! Beware the Butt Dyno, the correction factor is never what you think it is!

[fhptom]

The drive in the truck was a reminder of what my Mustang & Camaro felt like. You see I spend at least 8 hrs a day patrolling in a dead Crown Vic so when I get in my truck with its lower gearing and exhaust tones it reminds me of some of my faster patrol cars.

 

My 260 was dyno'd at 185 rwhp and has a R200 rear end w/4.11 gears and a Quaiffe limited slip. It was around 2300 lbs before I put my cage in so that is why it is quick around a race track. My stroker plans change daily, but I already have the bottom end(thanks to Ken Jones) complete and plan on using the N42 head I have in the car now. I am running 45mm OER triple carbs and MSD ignition. I am looking at using a ISKY cam with 530 lift and 256 duration to liven up the head a bit. Right now it has a MSA Stage III cam which is closer to 490 lift and 240ish duration.

 

The point I was trying to get at was does an S30 with 250 to 260 rwhp(which is what I am hoping for with my stroker) give the feeling of driving a vehicle with more power due to its lighter weight. ie my Mustang or Camaro patrol cars.

 

Since my track days are for fun and not to try to win some trophy for FTD I want it to also be exhilarating to the senses which for me is the feeling of being pushed back in the seat.

 

So I guess I was wondering if the feeling of power can be found not exactly equivalent et times

[JMortensen]

I had progressively built up my motor from ~180 whp to ~240 whp and at the very end there I finally hit the point at which I needed throttle modulation, I could no longer stomp on the gas at the apex. It was fast, and it pushed you back in the seat, but above and beyond that it's all somewhat subjective. I felt like it wasn't fast enough, which was why I decided to do a V8 swap. I had plenty of terrified passengers though, and even my wife who would get squirrely on onramps in the lower hp iterations was pretty much afraid to drive it with the triples...

[Daeron]

One major thing about the butt-dyno is.. the butt-dyno has about four or five different sensors, all of which read a different parameter. The Dyno Controller Apparatus (your cerebral cortex, or your brain stem, or your inner ear, or whatever) takes those inputs, multiplies them, and spits into your conscious brain this impression of power or that impression of power. Already in this thread, the descriptions of how power can feel are abundant; this is because the butt dyno gives us a smile of varying intensity; nothing more. We add the comments like "pushed back in the seat" versus "head pressed against the headrest" to give that some perspective, but talking about how fast a car is is a subject that takes excruciatingly long-winded and semantically perfect phrasing.

 

My CRX HF is a great example.. Heres the tranny gearing: 1: 3.25 2: 1.65 3: 1.03 4: 0.864 5: 0.694 Final Diff is 2.98:1 (In a CIVIC!) Second gear pulls are two totally different animals depending on whether I pushed first ALLLLL the way (ECU cuts fuel at 5200 RPM) or not. The motor is torquey as all get-out, but with these gears it takes a loong time to really feel any acceleration at ALL. Unless you watch the speedo, which just climbs, and climbs, and climbs, and suddenly holy CRAP, I AM DOING SIXTY FIVE IN A FORTY AND JUST BLEW BY A COP IN MY RED HONDA, AW CRAP.... That is a torquey motor thanks to a teeny tiny intake manifold supercharging my intake charge at mid RPM, low throttle. Easy shift into second at reasonable rate, reasonable throttle, if left unattended, suddenly I am in trouble without knowing it!

 

This is a conversation that can never be had often enough. It seems to me the more I have it, the more I pick up not just from other people, but from re-analyzing my own experiences.

 

Edit: Oh yeah, you *are* a cop. Tee-hee!!

Edited May 13, 2010 by Daeron

[Mayolives]

QUOTE:"just wondering if anybody has replicated that feeling with a N/A L-6 motor."

 

Yes. My buddy Mark has a stroker in his track car and I have ridden with him a number of times on track. His 240 isn't gutted and the stroker is not a high end build. Although I don't know that actual rwhp, I would guess it's no more than 250. The triples have that big "throaty" sound and the accompanying torque will pull you back in the seat. It definitely has that feeling you refer to.

Edited May 13, 2010 by Mayolives

[ZR8ED]

Butt dynos definiately don't work all that well.

 

My Z with a triple weber'd L29 and a 8k rpm rev limit (hit it in 4 of 5 gears..only 7400 in 5th) Now that FELT fast. Loud, harsh, no power below 3.5K. Estimated power 250 ish never had it on the dyno.

 

Fast forward.

Modded Vg30ET in the same car. Real dyno numbers 300hp/350tq. Fast, oh hell ya. It has a torque curve that will make a lot of cars cry..(mostly strung out Supras..hehehe long story) Now does it "feel" fast? "non car people" cry/scream/cover their eyes, "car people" comment that it is "pretty fast", and "we are going how fast?". The power comes on and stays on, no feel of a torque peak so to speak. Car feels kinda flat...Smooth almost. Weird eh?

 

Or maybe my butt dyno is broken?

 

Scott.

[ozconnection]

Interesting discussion.....I thought that I'd add my two bob's worth.

 

Torque is what accelerates you, power is what wins races.

 

Power is torque X revs.

 

So often is the case that an engine is modified to improve its power, by definition its torque by revs. Torque at high revs is achieved by improving the airflow capacity of the engine. This can be achieved by many methods, such as turbo or supercharging, by chemical means ie nitrous or by the conventional NA route with cams porting compression etc. We all know this.

 

To build an engine that 'feels' torquey, without having to drop two gears to get the thing "on song" is what I read the original statement to be.

 

A torquey engine at revs (a powerful engine) in my Cedric was never going to be the right choice as a truly functional street driven vehicle IMO. I built up my L28 to be responsive at low rpms and provide solid urge without having to "get on the boost" or "come on the cam" or anything else like that. It's there, all the time, just squeeze the throttle and it 'goes' no lag or delay. That's what I call a good responsive (read torquey) street engine.

 

Oh, and it CAN smoke the tyres if I want, but more importantly, come to a hill at 100km/h, stay in overdrive at 2.5k rpm and it stays there, just squeeze the throttle and it just pulls, just like something bigger although it isn't. It's these comfortable and effortless performance characteristics that give me a hard on every time I drive the bloody thing. Oh yeah, I'm excited alright.

 

And it's essentially a stock longblock and it originally pulled 0-100km/h in 13.4 seconds, now it's less than 10 seconds for the same marker. It idles smoothly, doesn't overheat in traffic, starts first kick everytime hot or cold and your nanna could still drive it to the shops. The coppers never give it a second look either (Not that it doesn't attact attention though).

 

I love my 'tractor'.

 

Cheers.

[woldson]

My need for speed has dropped considerably.

 

Over the years I've posted some pics and made comments of my friend Steve and his factory five ac cobra.

 

Pretty much all the goodies for a 351 Windsor, with tt.

 

I forget exact numbers, something like 820 rwhp, (at the time 3.0 rear) and weighs roughly 2400lbs.

 

At least now he can hit 58 mph from a dead stop at a light to the other side, four lane of course.

 

 

This car exceeds your understandable knowledge, it will cause the butt dyno to peg! The seats are kinda straight back, Yet you don't just feel like you getting pushed back in your seat, it is more like up, due to the seat having a slight recline. Four point seat belts help.

 

Pulling in fourth at around 140mph, the tires would start to break loose. Now he has street slicks. The sound of the engine, air and ginormous fuel pump, just kinda disappear at full boost.

 

All sense just gets pegged.

 

I just have one big s..tting grin, even after the rides are over.

 

About 30% of grown men are only good for 1 ride. It is kinda like, wow, no smile and a thanks, thats it.

 

Yes the car is grocery getter.

 

Yes it is wrong to speed, however, it only takes like 4 secs to go from 70 to 140. Then the massive breaks kick in. It is not like those long periods of time other need to hit those speeds.

 

 

This is why I've considered a na straight six, (probably not the l6) 250ish hp in a all around great car. 280zx big breaks and handling..

 

Just a fun car to drive. If I ever get the urge, I'll just re calibrate with a ride from steve.

 

I'll get the number off him later in order for some to even believe me.

 

 

He pretty much only nails it at the drag strip, things happen so fast with the car that you start to understand that reaction time is slow compared with the car.

 

BTW he is hitting 145/150 before the end of the 1/4 mile, runs out of fourth gear. (auto)

[fhptom]

Thanks for everyone's response. It is what I was expecting to hear and probably what I all ready knew. My car is quietly fast and was just wondering when I get the stroker done if it was going to be more in your face fast.

 

I have read about Marks car(thanks Myolive) and some of you other mid-eastern state track junkies and just wanted to re-vitalize my stroker build in my own mind. I am hoping to get in done during the HOT summer months and be ready for the fall track days.

 

So off to the shop to start on yet another motor for the Z.....

 

Tom