Engine technology thread.

[serialk11r]

EDIT: oh hey, okay thanks.
Can anyone provide 1LR-GUE info? That engine should have some very very long duration cams, I'm curious to see how they're set up (with dual VVT-i of course). That would give some insight on how a no-compromise performance motor should be tuned for top end power.

I can't think of any >7000rpm motors with only cam phasing aside from this one...wait actually BMW S85 is double VANOS, but ITB not Valvetronic...anyone have cam specs for that?

EDIT: Found spec sheet, will sift through it right now...argh I should be studying.
EDIT: Damnit, no actual specs :/

[Dimman]

Originally Posted by serialk11r

EDIT: oh hey, okay thanks.
Can anyone provide 1LR-GUE info? That engine should have some very very long duration cams, I'm curious to see how they're set up (with dual VVT-i of course). That would give some insight on how a no-compromise performance motor should be tuned for top end power.

I can't think of any >7000rpm motors with only cam phasing aside from this one...wait actually BMW S85 is double VANOS, but ITB not Valvetronic...anyone have cam specs for that?

EDIT: Found spec sheet, will sift through it right now...argh I should be studying.
EDIT: Damnit, no actual specs :/

What you could maybe do is take a look at bike cams, that operate in the 10k range, and maybe work backwards? Compare their timing/overlap at power-peak then figure out how close you could maintain that with less cam duration but with the advance/retard range of the VVT-i. Plus working under the assumption that the car would need to meet stricter emissions, too. (LFA made a big deal about hitting some tight Euro emissions level.)

Also the LFA has multi-stage (don't know if it's 2 or 3) intake resonance control, which can give some headaches with regards to scavenging since the timing and overlap will probably move around to optimize the acoustic effects...

[serialk11r]

I think I am really bad at searching for this kind of stuff or something...I can't find any cam timing/duration info! grrrrr can someone help lol.

Dimman good suggestion, bike engine would actually be a MUCH better indication because bikes have a lot less emissions considerations. As I said, I think the high EGR is for emissions as EGR reduces pumping losses, but increases charge temperature and thus reduces heat ratio. My hypothesis is that a bike engine has an advanced exhaust cam at low-medium speed to reduce EGR, and advanced intake for VE. It's probably unlikely that a bike engine has load dependent VVT right?

[old greg]

Here you go:
http://www.aperaceparts.com/tech/camsWS70872B.html
http://aperaceparts.com/tech/GSXR600.html

The only bike I know of with VVT of any kind is the ZG14 Concours. The VFR800 of yore had "VTEC" but it was more like Subaru's AVLS, using valve deactivation to improve combustion efficiency at low rpm.

[serialk11r]

Oh crap. So when I assumed bikes had VVT I was thinking of Berkeley FSAE car which runs on a Suzuki GSXR600 motor or something...I talked to someone on the team about cam profiles/timing and he said he could try retarding the cam by moving the cam gear. For whatever reason when I made that post I drew the conclusion that bikes must have on the fly adjustable timing -_____-

Hmmm looking at those cams, wow okay. Intake opens 19 degrees BTDC, exhaust closes 8 degrees ATDC. Does that sound like typical high rpm overlap on a performance car?

[arghx7]

Regarding the 1LR-GUE (LFA engine), here's the only thing I could find




What I'm getting from this is that the valvetrain is very lightweight. Due to the lack of mass it can achieve a greater opening area at high rpm even with a more mild cam. They intentionally did not use any kind of variable lift system (fixed or continously variable) for durability reasons.

The overrev fuel cut on this engine is at 9500rpm and it says that the engine was designed to rev higher than that for durability reasons, so that makes sense.

[Dimman]

Originally Posted by serialk11r

I think I am really bad at searching for this kind of stuff or something...I can't find any cam timing/duration info! grrrrr can someone help lol.

Dimman good suggestion, bike engine would actually be a MUCH better indication because bikes have a lot less emissions considerations. As I said, I think the high EGR is for emissions as EGR reduces pumping losses, but increases charge temperature and thus reduces heat ratio. My hypothesis is that a bike engine has an advanced exhaust cam at low-medium speed to reduce EGR, and advanced intake for VE. It's probably unlikely that a bike engine has load dependent VVT right?

Sorry if I was a bit confusing there about the VVT-i. What I meant was just look at basic bike cam profiles, and then advance or retard the timing around yourself on paper, as if it had VVT-i. Didn't mean to imply that bikes had it...

[serialk11r]

Nah you weren't confusing, I was just being an idiot.
Lack of VVT on bikes is another problem though, as the timing would be somewhat compromised to give low rpm stability :/ Well I guess these bikes do run >>10k rpm so it's okay to expect them to do well at 8-9k.

[old greg]

Originally Posted by serialk11r

Nah you weren't confusing, I was just being an idiot.
Lack of VVT on bikes is another problem though, as the timing would be somewhat compromised to give low rpm stability :/ Well I guess these bikes do run >>10k rpm so it's okay to expect them to do well at 8-9k.

Define "low" rpm.

Hell, even my old SV (redlined at ~11000) ran like utter crap below 3000 rpm. Just cruising around it wanted to be run at ~4-5000 rpm.

[serialk11r]

if you say so, 3000? rofl

[Dimman]

Originally Posted by serialk11r

if you say so, 3000? rofl

There are also different tune levels of similar motors you could compare. I know Yamaha has (had?) a sport-tourer that's motor is like a de-tuned R1 motor. Check the differences. Also difference between a Honda CBR600-blah-blah, and their naked 599 (Hornet?).

[serialk11r]

Hmmm well I dunno, seeing that those motorcycle cams were ~280 degree duration, and the 2GR is something like 240, intake closing maybe like 60* ABDC, and the motorcycle intakes open 30* BTDC, I guess we need to see what the FRS cams look like. Since they peak at 6600 (much higher than the 2GR's 4800), they will have longer duration...If they're like 270* duration then it would be utterly ridiculous that they are able to squeeze healthy torque at low rpm ranges out of the engine as almost half the charge would be blown back out! (the Prius uses ~270 degree cams with 13:1 compression!) The Toyota D4-S papers show "20% internal EGR rate" to be the limit. If they run that with a cam retard to improve VE, then the high EGR would be killing power as well. Then we could also expect that a longer cam with some overlap would see good gains at high rpm, but do bad things to low rpm torque, but increase fuel economy (lol, I'll take that...).

[Dimman]

Originally Posted by serialk11r

Hmmm well I dunno, seeing that those motorcycle cams were ~280 degree duration, and the 2GR is something like 240, intake closing maybe like 60* ABDC, and the motorcycle intakes open 30* BTDC, I guess we need to see what the FRS cams look like. Since they peak at 6600 (much higher than the 2GR's 4800), they will have longer duration...If they're like 270* duration then it would be utterly ridiculous that they are able to squeeze healthy torque at low rpm ranges out of the engine as almost half the charge would be blown back out! (the Prius uses ~270 degree cams with 13:1 compression!) The Toyota D4-S papers show "20% internal EGR rate" to be the limit. If they run that with a cam retard to improve VE, then the high EGR would be killing power as well. Then we could also expect that a longer cam with some overlap would see good gains at high rpm, but do bad things to low rpm torque, but increase fuel economy (lol, I'll take that...).

Try to find specs that have the duration @ .050" lift. That gives a better picture of 'effective' duration. Prius probably has low, gradual lift so a lot of those 270 degrees are probably at tiny (ie not really significant) lift numbers.

In the BC .pdf catalog they have some more detail about when events take place (only certain cams though, and not the stock figures).

http://www.briancrower.com/dl/06cat.pdf

[arghx7]

Here's some mostly apples vs. oranges specs to throw in from the 1960s 426 Hemi engine:



The "track" engines were NASCAR engines used back in the day, when teams had more flexibility in engine choice (I'm no NASCAR expert). The drag version was used in competitive drag events and the street version was the one sold in very limited numbers to the public. Even the street version had pretty aggressive cam that hurt low end torque. The 1966 version especially had insane duration and overlap as you can see.



valve lift vs cam degrees (not crank degrees)

dyno (flywheel horsepower) sheets, including a prototype mechanical fuel injection engine that never saw much use: