Coolstr85

lex luther- sorry to change the subject, but i saw that ur 95 sc400 was for sale, how much are u lookin for?

JZS14SEVEN

can of "liquid Schwartz"
never watched Spaceballs???
oh well.. nevermind

yes i've seen and read... IS3 turbo..
a bit different from my project..
simple, neat, & clean is my theme

new technology??? whatever buddy..
VVTi is half a step up from T-VIS
and a coupla steps behind BMW & Honda in the naturally aspirated HP per liter race

activating a solenoid is the least of your worries..
Fuel/ignition maps under various loads is the hard part.
fancy variable head stuff is great in a N/A motor..
to be able to play with volumetric efficiency through the head is definately ...
BUT with turbo there are so many MORE variables for you to play with
Are you ready to play??
can most standalone's take care of multiple cam timing profiles/ignition timing?? under various loads? Boost? whatever?

but hey, don't worry i'll make the trip to the Continental US if i get my "Paid Ride"

TGRich

Sorry dude, I've got my money on LL.

Lex Luthor

Actually, glad you changed the subject. Price is $14,700, you can get the details in the for sale section under SC's, i'm too tired to post a link. JZS14SEVEN, you've lost me with your playing around with volumetric efficiency, I suspect that's the biggest automotive term you could think of to throw around . Anyway, you're right and i'm wrong, Kay? I'm sure your ten year old GS has been well tuned at your DynoJet facility....

Richie, not going South, no worries. tggoodrich, just call me seabiscuit ....


....boostbiscuit?

JZS14SEVEN

not about right or wrong... i could care less if you're right..
VVTi is for fuel efficiency.. just like VTEC

in either case i'm not the one chasing my tail with problems

TGRich

LOL, boostbiscuit it is. Now how would you like that if it was to actually stick?


Tim

SC300T

I'd have to hang out on the fence on this one for awhile.... I would have tons of questions as well. The main one is how is the cam profile changed? Is it based on a call from the ECU via solenoid, or some vacuum or hydraulic means upon certain pressure/rpm? What controls this mechanism? Is it RPM only or a combination of RPM/Load? Obviously at WOT the changeover would be predictable enough so that any standalone could adjust appropriately. If a standalone has the capability like the AEM to automap to some degree, there would really not be much issue as the tables will do their own thing. That said, there could be other drivability issues and a few low speed vices that crop up, but nothing major, IMHO.

My car is basically a VVTI that is permanently stuck in a VVTI high rpm mode right now, if you know my car...
It has a few very small drivability issues, but nothing earth shattering. I get an occasional chug at low rpm and low throttle position that is not a/f related---something within the stock ECU that jumps the timing around. All things considered, I got good drivability with an SAFCII, so I'd guess that Lex could dial a VVTI in pretty close to ideal, if not perfect. My car runs good, and that's hobbling around town on a 268/270 cam profile with significantly more than stock lift, yet the ECU still does o.k.

Worse case scenario is that the VVTI would have to be modified to stay on the high cam profile--- not all that bad, especially if Lex does an SP63 and doesn't lower the compression too much.

Lex Luthor

JZS14SEVEN, you couldn't be more irritating. Who's chasing their tail around with problems? Not me, don't know where you're getting that from, and VVT-i is not for fuel efficiency, do you own one? Didn't think so. Nothing you say is based on any fact, if it was, you'd post a nice timeslip right now and shut me up. Where's those pics of your monster 1st gen GS? Your DynoJet facility you say you own? Your Autronic you say you bought? This thread is for sharing information and exchanging ideas, not busting someone's b@lls about something in which you have no technical standing to speak from. Go bother someone else who's willing to believe you know what you're talking about.

Scott, here's the story. The VVT-i is based on a call from the ECU via solenoid, and it is rpm and load dependent (it's not like VTEC, wrong again JZS14). Using most standalones to control it, i.e. Haltech E6K, will change it to an on-off affair, this is what Toyomoto and others do, and these guys have made 600+ rwhp like this. The other alternative is to leave the stock ECU controlling the VVT-i, and to use the standalone for fuel and spark maps, either way we'll be leaving the stock ECU in the car to control certain functions. At the very worst I could do this and avoid all variable valve timing problems completely. Again, if Lujan/Toyomoto can click a hi nine in a street car with the same identical motor, i'm sure we'll be able to tackle it . Have faith. Compression will be 8.6:1 Scott. The VVT-i definitely makes a difference, it's extremely responsive, when someone else drives the car (including mechanics), they usually spin the tires off the line by accident just because the revs come up so quick, i'm not joking. This thing with the six in it is just about as quick as my SC400 with the eight. Hoping it'll spool quick enough to be able to road race it if I want, Lar assures me it will. Long story short, I wanted a '99 or 2K SC to build upon, since they are the culmination of the SC run and have all the best improvements, so I wasn't exactly given a choice with the VVT-i, it kinda came with it, but I see it as a potential benefit, not a hindrance, just some extra blood and sweat. If it becomes a stumbling block at some point down the road, i'll swap to a regular GE head and go with Brian's cams like you've done Scott. So what was the big deal?

JZS14SEVEN

i never said it was exactly like VTEC.. only that the "function" was the same..
if you think about it, it IS for fuel economy.
Otherwise you'd have a more agressive cam profile ALL the time..
and your low RPM characteristics would suck, ALL the time.

better find out HOW lowering the compression is gonna help you in the response catagory
VVTi is NOT goin to get you back any lost response from changing to 8.6:1 compression..

Sucker, born again

Coolstr85

dude. VTEC is not for fuel economy, VTEC is for ading more HP at higher RPM's. the fuel saver in hondas is the VTEC-E. that the HX model civics and a few other cars came with. those are the fuel efficient ones. all the ones with VTEC, the GSR integras and the EX and SI model civics for instance, were the more expensive versions of those cars. the VTEC is there for HP, not for fuel economy, the fuel saver cars were the ones without vtec and the HX fuel efficient models with VTEC-E

Lex Luthor

Dude, don't go away mad, just go away. Find a clue. At different points in the powerband of an engine, differing volumes of air and fuel are injested, flowing @ differing rates, said engine will require that the valves be open by a certain amount and for a certain time at one point in the powerband, and by a different amount and a different duration @ another point in the powerband. Utilitzing technology that will allow you to manipulate cam profiles to achieve this goal is proven to work and has NO downside other than the requisite additional comlexity of the system itself. This is why variable valve timing and variable-runner intake technology is big right now. Shut yer pie hole for a moment and try to learn something instead of constantly busting b@lls. Oh, and you DID say it was 'just like VTEC' - those are your exact words, kinda hard to get caught out there and then deny you said it when your post is just a few inches above. Duh. Lastly, VVT-i WILL help responsiveness on a motor with lower compression as compared to a motor that does not have it, if you want to argue that point, go bother Lance HoLung @ Toyomoto. You probably think he doesn't have a clue either. Noooobody knows better than you . You know, i've built up over 25 cars/trucks/bikes for myself (these guys all know this), not to mention work i've done for others, don't really need you to second-guess me, go play with your fictitious DynoJet facility. Who's the sucker now? Now be out, you're peppering my thread with ignorance...

TGRich

Score:

Boostbiscuit- 113

JZSwho?- 0

aliga

iTrader: (147)

LL - Mama said knock him out.

SC300T

hehe... Boostbiscuit... I like that.

Just thinking aloud here:

Low end torque on a turbo motor is reliant on exhaust velocity to turn the turbine at or near the surge line. below this point the engine is really the same as an NA engine. With 8.6:1 Lex is going to have some lag on a 63. Its not going to be super laggy, but the turbo will probably begin making boost around 2500rpm, with full boost around 3700rpm, perhaps 4000rpm.

Below the positive boost point at around 2500-3000rpm and below, the VVTi is definitely going to help the engine's torque output through better intake velocity/turbulence through a short duration cam profile. This also increases VE which helps spool.

I can tell you from first hand 2JZ turbo experience that increasing valve duration reduces torque output, spool and low end power. Going from the stock cam to a 268/270 setup reduced torque output below 4000rpm, increased the torque peak from around 4500rpm to 5200rpm. It also placed a big net gain of power over around 5500rpm. I went from crossing into boost as low as 1700rpm to more like 1900rpm. After 1900rpm boost builds more slowly. With full boost by around 3200rpm. The nice thing about my setup is that full boost and the torque peak are more separated now, which makes it easier to drive as there is less of a sudden onset of power when the boost comes on.

Now what was your thinking on why the VVTi won't help on the low end???????

Just curious.

Lex Luthor

gadg, you'll be the first to see it, and the first to race it . I've got us scheduled for hot laps @ E-town, then Limerock, start increasing your tyre budget . Maybe Skip Barber for us next year, that or Roy Hill . Deb says i'm only allowed to do 'that straight line racing' , and she wants me to put a cage in 'Boostbiscuit' , I laughed and told her 'baby, it'll be way too slow for that, gotta be runnin' nines before i'm willing to do that' , 'nine what's??' she says....'nevermind'.....

Scott.....the only guy that likes to be more technical than I, me and gadget wonder about meeting you someday. As usual, I agree with you 100%. As far as your assessment, i'd be perfectly happy to start building boost around 2500rpm, and didn't expect to see full steam until 4 grand, 3700 would be great (would go with a converter that would flash in that range). You and gadget have these freakin' turbos that spool like off idle, back in the day doin' GN's, a 60-1 was big, a T70 was a ferris wheel . Going up against everyone and their mother with a Trust T78 kit on their Poopra, i'll be underway far quicker, Lar assured me it will totally spool quick enough to road race it, i'd be pretty impressed if it could with a .81 housing, but they say this is some turbo, we'll see. I'm chatty today, eh? Only thing left will be to sort out the transmission, and at some point a ltd slip. Boy do I have a big pile of parts.......
-JonJon