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Discussion Starter #1
hey does anyone know if there is a way to make that high speed or high rev cam turn on any sooner than 6200 rpm?? it would be very nice if it turned on at say 4200 rpms.
im not familiar with these engines and dont know whats involved here.....
thanks
 

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You don't want this, really. The 'second' cam doesn't start making more power than the first until somewhere around 6000 RPM, in otherwords, where the switch happens already. Lower the crossover and you'll make a big hole in your power delivery.
 

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Discussion Starter #3
hey andy, sup!
i dont really understand why there would be a hole in the power delivery....i admit, im not at all familiar with these engines and how they work, and what works with them....(sorry, but theyre not engines that given the choice i would choose to modify) be that as it may, this is what we have to work with for now....
so i guess my question is, how can we get that performance lower down in the rev range and have it carry through equally or greater through the top than it already does....
lets face it, this car is a pooch until 6200rpm, and even then it leaves a little something to be desired....
dont get me wrong, i love the car, but im always looking for a little more power....
 

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Don't you think the manufacturer would have set the transition at 4,200 if they could?

Why not 2,100 and it would be even better, right?

There are reasons (i.e. physics, engineering) why it's where it is.

This isn't to say you couldn't modify the engine to make more power, but it's not as simplistic as having the 2nd cam actuate at a lower RPM.

-Jim
 

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I drew some pictures. Let me see if this makes any sense.

Imagine the blue-green curve to be the low-rpm power curve and the red curve to be the power curve for the high rpm cam. Pretend that they cross at 6000 RPM.



Now let's imagine that you've reworked the ECU to allow the changeover to happen at say, 4000 RPM. The fat line shows the result. See how the too-early changeover leaves you running on the high-rpm cam and making less power than if you stayed with the low rpm cam?



Now, let's look at what happens if the changeover happens right at the point that the two power curves cross...



You get the best of both cams. Think of it this way, if the high rpm cam always made more power, why would Yamaha, Toyota and Lotus even bother to include the low rpm cam? It would just be extra weight, extra cost and extra complexity.
 

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The only way to change the cam change is a stand alone. Add some flow and you can turn it down and low as 5800 (So far for me) and still get benefit.

I don't know what lotus did at the cam change but Toyota pulled fuel to give the cam change a distictive kick in the seat. Not a good thing for a mid engined car IMHO. So I assume Lotus corrected this problem but they may not have. If so a little more fuel allows for a little more timing and a lot less upsetting cam change wiht a little longer power band.
 

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Discussion Starter #7
i understand what u all are saying....
i think i oversimplified my question....what im trying to say is maybe theres a combination that works better...maybe with some head work and increased all around flow, a little more fuel volume, can we change cam combinations?
maybe not, but im just asking.....damn, i just dont think theres much we can do with this motor....i would like to see 30 to 50 more horsepower at the wheels....i think we can find the first 20 fairly easily, its the next 25 or 30 that will be difficult.
 

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You're not going to find an easy 20 HP and then 30 more. If you need much more oompth than presently you need more cubic inches, or some forced induction. You could get some more midrange oompth to smooth out the transition to the high cam. This would involve a low cam lobe that is more RPM oriented than stock, but less so than the high cam. The cost is that the low end would be softer. There are always tradeoffs. One nice thing about the mild low cam is that the car can cruise in 6th gear at surprisingly low RPMS. Cars like the S2000 are dead as a doornail in 6th in the lower RPMs. Below 6000 the 2 liter S2000s accelerate about the same as a Miata or Civic. Some folks never even use 6th much on that car. To go fast in the S2000 and the Elise, you need to rev the thing in the correct gear for the occasion.

I'd be surprised if much more than about 10 extra HP at the wheels can be found without significant side effect. Lotus is already delivering the car to us with a few more ponys than it's Celica GT-S version. With the likely amount of extra HP that can be generated with things like intake, exhaust and some tuning, the AFTER car won't feel massively different than the BEFORE car. You can add HP sometimes by getting all of it past 7500 with little change before that point - this doesn't seem to be what you want.

What exactly is the reason for your concerns? I ran an autocross event last Sunday using easy off idle launches and about 4000 Rs and still beat every Vette for example.

Are you trying to do drag racing? This is not what the unique qualities of the Elise are best suited for...

Do you just want more grunt in general, the feel of getting pushed harder in the seat of your pants? Maybe try an engine swap to a 2.3-2.4 liter + motor tuned for more low/mid and lower RPMs? If you explain a bit more perhaps some ideas can be offered.
 

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On the contrary the 2zz responds well to n/a mods.

The car dynos at 160 according to SCC.

There are several mr2s with 2zzs knocking on 200 whp. There are a number of celica that are just shy of 200 with only bolt ons.

40 h/p is there.

--Get a light weight flywheel and pullies (shy away from the crank pulley)

--Get rid of the air box and put a short tubular intake with a conical filter close to the side vent.

--Have a better flowing exhaust ie straight through muffler made.

--Install an after market header built for the celica or have yours ported for the same 4-5 h/p gains.

--Figure out a way to make the pfc work and get it tuned.

--You will be at about 180 (maybe 190) to the wheels.


Then if you want more go inside the engine or pay me to. ;) There is more benefit here ecause you can extend the rpm range of the engine as well as improve flow.

Here are the areas of opprtunity lef tby manufacturing compromises/ All IMHO.

The good news:

Throttle body:

The throttle body is 65 mm and is more than adequate for 300 h/p+. It matches the intake inlet perfectly. I would not touch it.



Intake manifold:

The intake is very nice except where the extruded aluminum runners attach to the cast portions of the manifold. There is some cleanup that can be done there to pick up a couple ponies at the head side of the intake. The other end of the runners is not accessible without cutting the manifold open. Cutting it open is not worth doing to get to the inside IMHO.





Ported:




The exhaust manifold:

The collector leaves a little to be desired. There are dyno proven 5 h/p gains from porting the head side of the manifold.



Ported:Can't find a pic right now

The cylinder head

It is awesome. There is a little slag in the seams of the ports that should be removed as well as shrouding around the valves. Removing the valve shrouding & slag should be wort more than a couple ponies. Maybe as much as 5-10.







Ported:

intake



exhaust


A newer set of valves will help flow and reliability. These are a set of Ferrera valves (SP) in my motor. The black valves are stock.







The valve cover:

It has a sprinkler system to lube the cams. Ingenious. Way to go yamaha.
 

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That's quite a bit more than simple bolt-ons to gain the "40 Hp" you mention... And the Elise already has more RWHP than the GT-S. And our cars are under warranty too.

The OP seems to want more of a shove in the back earlier. The 200 RWHP car you envision won't do this it appears. Maybe the OP will chime in. High revving small displacement motors need to be revved to the limits. That's where your +40 HP appears to lie - upstairs. Note that the OP is asking for more BEFORE the high cam kicks in... More go, and well before 6000 RPMs.

Basic power bolt ons won't gain you 40 HP on this car. The guy seems to want something like 25-35% more torque.
 

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FOrtunately I'm no engine guy, but it seems like mods like that will take the car from being a reliable daily driver to a tempermental garage queen, labor intensive to keep running right,

Not that theirs anything wrong with that.
Chris;)
 

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Nice work

LittleRocket, nice bit of porting work there. I look forward to any before and after dyno sheets.

To the naysayers I have to believe that these subtle flow improvements will make a welcome difference without sacrificing reliability. And it's only a bit of work to clean those paths up. It's not like he's dropping in a radical cam, a turbo or a 6 lb flywheel, he's improving a little slop that is a typical byproduct of mass manufacturing. By reducing turbulence and he makes the engine breathe better. Explain to me how that makes the car a temperamental garage queen?

Just because you know nothing about a subject doesn't mean you need to make derisive or uninformed comments on it.
 

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jdw,
if you read my post you will see I prefaced it by saying I know nothing about engines. but when you get into changing flywheels porting etc. it DOES kill your warranty (and many of us don't have fat wallets to pay for problems derived from these changes).

It's certainly good to see people willing to experiment and mod their cars, I'm too chickens*** to do it.

thanks for pointing out my inadequacies;)

Chris
 

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Guys. I have done this to my car already so it isn't theory.... I drive it every day and in traffic it is easier to drive than with the stock (1zz) engine. A little scary in the wet if you aren't careful in 1st & 2nd gear. My midrange is significantly better than the original motor. Most of it is due to the apexi PFC. If you want to get greedy you could also add a 1zz crank and up it to that 30% more torque you are looking for. Sadly it jsut takes money but look at the bright side. All of this is alreayd worked out and you guys don't hav eto reinvent the wheel. :)

Midrange question answered here:

http://monkeywrenchracing.com/mwr_celica_gts.html

2. Want to talk about low- and midrange? How's +18 wtq at 2500rpm? That's a gain of 20%, like going from a 1.8L to a 2.3L engine. The torque gains continue across the midrange, with +18wtq at 3500, +~11wtq from 4500-6000. That's a difference you can really feel while driving the car. It pulls much stonger without hesitation from any engine speed.
Dyno of an injen intake and an Apexi PFC.





I understand the car is under warrantee and I wouldn't want to loose it on such a unique car either. But if you want more power than bolt ons will give it is going to have be sacfrificed. Also keep in mind the car can be reengined for about 1500.00 for a used motor. That is dirt cheap for an exotic. Dirt cheap.

The elise only has 5-10 more h/p than a celica at the wheels according to SCC's dyno.

I guess I am going to have to take mine to the dyno before I get that header wrapped up. LOL. Would be nice to get a before an after run.....
 

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zvezdah1 said:
FOrtunately I'm no engine guy, but it seems like mods like that will take the car from being a reliable daily driver to a tempermental garage queen, labor intensive to keep running right,

Not that theirs anything wrong with that.
Chris;)

The beauty of technology my friend. The car has variable valve timing. Unlike a standard engine wihtout it the valve overlap can be reduced at low speeds to dramatically increase the low end torque and keep the engine very civil. And increased to make it flow better when you want it to.

Further more the variable cam lift makes for a race only cam profile in the high rpms with zero sacrifice of the drivability on the low speed cam. It is a little more complicated than shimless buckets but worth it the extra mechanicals IMHO.
 

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Re: Nice work

jdw5155 said:
LittleRocket, nice bit of porting work there. I look forward to any before and after dyno sheets.

To the naysayers I have to believe that these subtle flow improvements will make a welcome difference without sacrificing reliability. And it's only a bit of work to clean those paths up. It's not like he's dropping in a radical cam, a turbo or a 6 lb flywheel, he's improving a little slop that is a typical byproduct of mass manufacturing. By reducing turbulence and he makes the engine breathe better. Explain to me how that makes the car a temperamental garage queen?

Just because you know nothing about a subject doesn't mean you need to make derisive or uninformed comments on it.
Thanks! He must have ESP. Mine (tom'S) is only an 8 lb flywheel. The designers of the stock flywheel had a 2500 lbs car in mind mine is lees than that by several hundred and you guys is even lighter.
 

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zvezdah1 said:
jdw,
if you read my post you will see I prefaced it by saying I know nothing about engines. but when you get into changing flywheels porting etc. it DOES kill your warranty (and many of us don't have fat wallets to pay for problems derived from these changes).

It's certainly good to see people willing to experiment and mod their cars, I'm too chickens*** to do it.

thanks for pointing out my inadequacies;)

Chris

The beauty of a federal car is that it is covered by the US's warnatee act. They must prove that an after market part caused the damage before they legally can deny warrantee work.

So intakes, exhaust, headers, pulley's and flywheels ar efair game just like any other car. :clap:
 

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So in the power fc dyno above...the device helped gain about 10 HP over the stock Toyota ECU. And the Elise delivers about 5-10 more than the stock Toyota ECU. Can the +40 HP guy please provide some before after dynos?
 

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Sorry I haven't dyno'd my car yet. I was wating to spend that last 200-300 at the end of my mod trail. I still have to build a header for my car but just for curiosity's sake I will look into getting it tuned this week.

This dyno is not my car. This is a celica guy with the below mentioned bolt on mods. Stock celicas average about 150-155......

Injen CAI, Custom Exhaust, Fidanza Flywheel, Trial Header, Power FC

 
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