MR2 Owners Club Forum banner
21 - 40 of 68 Posts

·
Premium Member
Joined
·
13,459 Posts
75 mm ID is probably good enough, but there's always the chance of unlocking some more power there. Especially once cams are added to help the breathing out. ...or if someone is a glutton for ~200 cc more capacity and they choose to do some budget stroker action. :)
Actually I think you were right initially... closer to 70. I just measured mine, it's ~73mm at the inlet, but it tapers a little. Maybe it's 71 or 72 at the throttle plate, but I don't have the tools to get in there to measure.
 

·
Registered
Joined
·
1,694 Posts
I know that some of the RAV4 boys have been using throttle body adapters like these to fit larger TB's on their cars but whether there is any measurable improvement from doing this I don't know:

https://www.lceperformance.com/searchresults.asp?Search=throttle+adapter&Submit=Submit

Boring the TB is another possibility, I've inquired with Maxbore about it, he says he is doing the 2GR TB's and he can get a few mm out of them.

In light of Marc's comment I would put my focus on the exhaust and maybe pnp the exhaust ports and port match the exhaust runners and consider possibilities for redesigning the exhaust for enhanced scavenging but given the dimensional and packaging constraints this may be impractical.

Doing some more soul searching on this question, we do have informally a VE profile that looks like this based on Marc's dyno measurements:

RPM VE
2000 80
3000 86
4000 98
5000 107
6000 100
7000 98

So it becomes a question of what can we hope to accomplish in the best of all possible worlds and would it be worth the effort.
 

·
Registered
Joined
·
1,043 Posts
Discussion Starter · #23 ·
Peak VE on really highly tuned engines can be 110-120%, and carry out well over 7k RPM. So there's probably a bit more torque to be had, even around torque peak, AND if you can carry that out another 1000 RPM, then decent power. But like I said, you're going to be limited by head flow.


I doubt there's much power in the exhaust ports themselves, but I bet there are some sharp turns right around the valve seat for packaging purposes (to keep the exhaust manifold down lower in the engine bay). You can probably get a little extra flow there, but if the whole port has a really sharp turn into a low port height, it might be tough to see large gains there. Does anybody have good pics of the 2GR-FE head ports?
 

·
Registered
Joined
·
1,694 Posts
Does anybody have good pics of the 2GR-FE head ports?
Steve Godfrey posted pics of his pnp heads on the Ozzie mr2 forum some time ago. By the way if you haven't seen it he has a standard-setting built 2GR race car. He got fed up with 3sgte breakdowns and made the logical jump.

I have some spare heads lying around I will shoot pics when I get to the shop.
 

·
Registered
Joined
·
9,223 Posts
So how hard is it to fix the known "issues"? If the exhaust ports are part of the issue is there enough meat in the heads to reshape and open up the exhaust ports? Are there cams available for this engine? I think one of the key advantages the VQ engines have is that they were also designed to be in performance applications like the 350?370Z and Infiniti Coupes, not just sedans, mini vans, and cross overs.
 

·
Premium Member
Joined
·
13,459 Posts
So how hard is it to fix the known "issues"? If the exhaust ports are part of the issue is there enough meat in the heads to reshape and open up the exhaust ports? Are there cams available for this engine? I think one of the key advantages the VQ engines have is that they were also designed to be in performance applications like the 350?370Z and Infiniti Coupes, not just sedans, mini vans, and cross overs.
Monkeywrench racing sells re-grind cams in both 256° and 266° duration (I find myself wondering, which is the better option...). https://www.monkeywrenchracing.com/product-category/lotusevora/evoraenginecomponent/evoraqcamshafts/

It is too bad that Toyota hasn't put this motor in a performance application. If they had, it's entirely possible that there would be some better OEM parts available that could be used to upgrade. That said, given that it IS a Camry / Minivan motor I find it pretty impressive that it makes the power it does with minimal effort (headers, intake, exhaust gets you to very nearly 100hp/L, at the crank).
 

·
Registered
Joined
·
9,223 Posts
Monkeywrench racing sells re-grind cams in both 256° and 266° duration (I find myself wondering, which is the better option...). https://www.monkeywrenchracing.com/product-category/lotusevora/evoraenginecomponent/evoraqcamshafts/

It is too bad that Toyota hasn't put this motor in a performance application. If they had, it's entirely possible that there would be some better OEM parts available that could be used to upgrade. That said, given that it IS a Camry / Minivan motor I find it pretty impressive that it makes the power it does with minimal effort (headers, intake, exhaust gets you to very nearly 100hp/L, at the crank).
Agreed. Gouky showed just how choke off it is from the factory. Some big nasty cams in it would be sweet
 

·
Premium Member
Joined
·
13,459 Posts
Fun story actually, about it being a "Camry motor".

Was at the track last year, and a friend of a friend was there in an E36 M3 (not huge power, but not a slow car either). My friend had gone around introducing people and their cars to him earlier in the day, and had introduced me as "Alex has an MR2 with a Camry motor", and left it at that.

We were in the same run group. It was the second or third session of the day, and I had been running hard for about half the session, then did a gentle lap to let everything cool a bit. He caught me at the end of that cool-down lap. I gave him a point by as I apexed the last corner, and by corner exit he was basically next to me, with a bit of a run on me. At that point I decided to go for it again, put my foot down, and, to put it simply, walked away from him. Several car lengths by the end of the straight. He came up to me after that session with a somewhat amazed look on his face wanting to know "how much power does that thing have???".
 

·
Registered
Joined
·
9,223 Posts
Fun story actually, about it being a "Camry motor".

Was at the track last year, and a friend of a friend was there in an E36 M3 (not huge power, but not a slow car either). My friend had gone around introducing people and their cars to him earlier in the day, and had introduced me as "Alex has an MR2 with a Camry motor", and left it at that.

We were in the same run group. It was the second or third session of the day, and I had been running hard for about half the session, then did a gentle lap to let everything cool a bit. He caught me at the end of that cool-down lap. I gave him a point by as I apexed the last corner, and by corner exit he was basically next to me, with a bit of a run on me. At that point I decided to go for it again, put my foot down, and, to put it simply, walked away from him. Several car lengths by the end of the straight. He came up to me after that session with a somewhat amazed look on his face wanting to know "how much power does that thing have???".
Awesome...lol
 

·
Registered
Joined
·
1,043 Posts
Discussion Starter · #30 ·
Monkeywrench racing sells re-grind cams in both 256° and 266° duration (I find myself wondering, which is the better option...). https://www.monkeywrenchracing.com/product-category/lotusevora/evoraenginecomponent/evoraqcamshafts/

It is too bad that Toyota hasn't put this motor in a performance application. If they had, it's entirely possible that there would be some better OEM parts available that could be used to upgrade. That said, given that it IS a Camry / Minivan motor I find it pretty impressive that it makes the power it does with minimal effort (headers, intake, exhaust gets you to very nearly 100hp/L, at the crank).
Lots of places will regrind cams, and it's not like either spec is taking off a ton of the base circle. I wonder how hard it'd be to sort out the lifter and valve tip shims to put valvetrain geometry back in sync?


The MWR setup seems like the easy button, but it feels like they're tacking on quite a premium ontop of a reground set of cams with a shim kit to correct geometry. Or maybe I'm wrong and it's a huge PITA to sort out the shim thing...


With dual VVC, I don't see why a "sporty" engine usage case wouldn't want the larger duration cams. There really isn't a huge low down penalty to higher duration cams. See an E46 M3 S54 engine for a perfect factory example of this.
 

·
Registered
Joined
·
1,043 Posts
Discussion Starter · #31 ·
Fun story actually, about it being a "Camry motor".

Was at the track last year, and a friend of a friend was there in an E36 M3 (not huge power, but not a slow car either). My friend had gone around introducing people and their cars to him earlier in the day, and had introduced me as "Alex has an MR2 with a Camry motor", and left it at that.

We were in the same run group. It was the second or third session of the day, and I had been running hard for about half the session, then did a gentle lap to let everything cool a bit. He caught me at the end of that cool-down lap. I gave him a point by as I apexed the last corner, and by corner exit he was basically next to me, with a bit of a run on me. At that point I decided to go for it again, put my foot down, and, to put it simply, walked away from him. Several car lengths by the end of the straight. He came up to me after that session with a somewhat amazed look on his face wanting to know "how much power does that thing have???".
Sounds about right. I love me some E36 M3 (owned 2 over like 7 years), but they weigh about 3200 lbs in street trim, ~3000 lbs in "moderately stripped track trim", and will put down about 230-240 rwhp with all the usual bolt-ons. Fun, torquey engine, but it's not a rocket ship at all. A 2GR swapped SW20 probably has ~200-400 lbs on an E36 M3, and puts out about 30-40 rwhp more with a broader powerband.
 

·
Registered
Joined
·
184 Posts
Lots of places will regrind cams, and it's not like either spec is taking off a ton of the base circle. I wonder how hard it'd be to sort out the lifter and valve tip shims to put valvetrain geometry back in sync?


The MWR setup seems like the easy button, but it feels like they're tacking on quite a premium ontop of a reground set of cams with a shim kit to correct geometry. Or maybe I'm wrong and it's a huge PITA to sort out the shim thing...


With dual VVC, I don't see why a "sporty" engine usage case wouldn't want the larger duration cams. There really isn't a huge low down penalty to higher duration cams. See an E46 M3 S54 engine for a perfect factory example of this.
That engine is a bad example because it has ITBs to help the power drop off at lower rpms. Unless you plan on using ITBs on the 2GR, there is no comparison.
 

·
Registered
Joined
·
1,043 Posts
Discussion Starter · #34 ·
That engine is a bad example because it has ITBs to help the power drop off at lower rpms. Unless you plan on using ITBs on the 2GR, there is no comparison.
ITBs don't really do much that a good single TB setup can't do for power potential. They do have less volume behind throttle butterflies for transients (talking few msec here).

Look at a Nissan VQ35HR with dual VVC for the same example - big duration cams are fine even down low.
 

·
Registered
Joined
·
272 Posts
ITBs do almost nothing for power improvement, it's all about throttle response (and sound). ITBs will improve throttle response dramatically (mileage may vary depending on how the OEM set up their throttle). A cable ITB setup on a 2gr will feel much more responsive than a stock e-throttle on a stock intake manifold.
 

·
Registered
Joined
·
1,043 Posts
Discussion Starter · #37 ·
I'm not going to debate theory here. I'll just leave a link to this article for anyone who wants to see what happens when theory is put to test.
Not really sure what that shows about ITBs vs. a well designed single TB intake manifold with large plenum. The factory VQ intake manifold is massively compromised to fit a small volume under the factory hood, so of course going to an "infinite plenum volume" condition like an ITB represents would show a huge benefit.

F20C1 (that has a much better factory intake manifold) making a tad less peak power, but more midrange torque (again, infinite plenum can help cylinder filling at some RPM ranges):

 

·
Registered
Joined
·
184 Posts
Not really sure what that shows about ITBs vs. a well designed single TB intake manifold with large plenum. The factory VQ intake manifold is massively compromised to fit a small volume under the factory hood, so of course going to an "infinite plenum volume" condition like an ITB represents would show a huge benefit.
@DefSport Wow, you read that entire article that is all you got from it? Looking back at that section in the article, I can see that you have ignored a lot of information so I will just insert the direct quote on the matter.

"We realized that at this point the head wasn’t a restriction and that until we found the real bottleneck, wouldn’t see the gains from the head porting. So what did we do? We popped the top.

What is popping the top, you ask? Well, on a VQ35, the upper intake plenum is bolted to the lower intake plenum. When you pop the top, you remove the top plenum cover in the middle of a dyno pull to see how much power the intake runners would make if they were breathing in fresh air, without having to draw through the confines of the upper plenum cover, throttle-body, and piping. Now keep in mind that we already have a custom upper intake manifold with a 90mm throttle-body. The engine went full lean and we aborted the dyno pull. This was great news, as the engine is tuned by throttle position only. If it’s going lean, it must be flowing more air. So after adding a ton more fuel and popping the top again, the car put down 360 whp. The next logical step was to figure out a new intake for the car. Now a single throttle-body with drive by wire is great, but ITBs are ridiculously awesome. They have a lot of advantages, too. First of all, with such a large, aggressive cam, the engine doesn’t create very much vacuum. And with a large plenum like the one we had previously, the airflow through the plenum is horrible—the engine is constantly surging and will not run below 1,500 rpm. The throttle response is very slow because any throttle change required first filling the plenum with air before that air went into the cylinders."


I don't see any mention in here about a stock VQ intake manifold but I do see mention of a custom plenum with single throttle body.

As for the the F20C engine, this is yet another apples to oranges comparison. The intake system of the 2GR engine comprises of a dual variable valve timing system that in variable length intake system design solely to optimize torque output and engine manners at low rpms. The F20C uses VTEC, a valve lift system that uses a mild cam profile at low rpms to optimize torque output and low rpm engine manners while then switching to a more aggressive cam profile with higher lift and duration at high rpms. Variable valve timing is a great system, but as far as enabling a low idle while making peak power at a high rpm, the valve lift system is superior. Even Porsche, on their 9000 rpm revving GT3 engines, combine all three of these technologies (dual variable valve timing, valve lift, variable length intake manifold) to create a well mannered high performance street engine. The primary benefit of an ITB system is that it allows you to achieve this well mannered high performance street engine concept (and engine that has a low idle speed and high peak power rpm) without the aid of variable valve timing, valve lift, or variable intake length.

This is why I posted here in the first place, to state that comparing the 2GR-FE to the S54B32 is an apples to oranges comparison unless you are going to put ITBs on the 2GR-FE. Likewise, comparing the 2GR-FE to the F20C is once again apples to oranges unless you are going to incorporate the valve lift system to the heads of the 2GR-FE. Want to make an accurate comparison of the 2GR with another engines, compare it to something like Ford's 3.7l Duratec V6 or even the Coyote because these engine use similar head designs and single plenum intakes. The coyote even has similar intake and exhaust valve sizes in Voodoo form.

Also, going back to the original comparison made of how power adders affect the engine, the technology use to achieve the power is far more important than just the cylinder count. I think finding an engine with similar head design and seeing how much hp per liter it generates with various power mods is a more realistic view of what similar mods would do on the 2GR-FE. We don't expect power adders to make the same difference on a NA engine as they do on a turbo engine. So why expect power adders to have the same effect on a dual VVTi only engine as they do on a ITB or valve lift engine?
 

·
Registered
Joined
·
1,043 Posts
Discussion Starter · #39 ·
Not going to bother quoting all that, just going to say if you think adding VTEC to a 2GR-FE makes it “equal to” an F20C1 (FA20 is a Subaru engine), then not sure we’re on the same page on internal combustion engine theory.

Even a custom plenum on a VQ35 is compromised like I said, the ports and max shape of the plenum is dictated by the lower plenum. Ive owned and modded a rev up VQ35DE, so been there, done that.

Anyway, adding plenum volume can help in some cases, but not always on peak power (see F20C1 dyno). If you think ITBs always make more steady state peak power, well, I’d say try to find the engineering principles on why that would be. I think you’ll struggle to get there.
 

·
Registered
Joined
·
184 Posts
@DefSport I've clearly stated what the main advantage of an ITB system is in my previous post. So I have no idea where you are seeing me say "ITBs always make more steady state peak power". Having a verbal conversation with you would be down right insanity because you are even trying to shape written literature. Besides, I don't see how engineering theory could trump an actually controlled experiment. Oh well, you clearly know all the things so I am done with this thread. Hope your budget 2GR build goes well!👋
 
21 - 40 of 68 Posts
Top