3GENJDM: Gen3 Debate

[kblake]

If that's not true, then where are all of these low mileage rear clips coming from?

Did the PO of your donor clip just get bored with the car and decide to junk it, rather than sell it?

I realize there is no LAW that says they have to get rid of the cars by a certain mileage. However, it IS more cost effective for them to do that, and buy a new car, and that seems to be what many of them do.

I don't know how you can have been around the community for four years and have never seen a CT20b failure thread. I know of at least two of them that failed locally, here in Portland. I'm certain I can find at least a couple of recent threads about 20b failures on "the other board", however we are forbidden to post links to that board, so you'll have to search them out yourself.

The fact of the matter is, ceramic is more fragile than Inconel, and thus a turbo with a ceramic turbine wheel is probably going to fail before one with an Inconel wheel. Toyota recognized this, and has never imported a car into North America with a ceramic turbine.

Ken

[PETC]

Most of the clips I've seen come from either front end collision cars, or cars that were sold at auction by repo guys, cut, and shipped to the states.

They're mostly low mileage not because of the fact that they sell them on purpose, but because 50K miles driving around Japan is ENOURMOUS. It can cost you hundreds of dollars to drive somewhere in Japan, so lots of people just don't drive a lot.

As I said, I wasn't saying you were wrong... I've just never seen a thread about a CT20B failure where the turbo hadn't failed just like all the CT26 failure threads I've seen. Most were just old and blown or had too much shaft play, but I've never seen a thread that came to a conclusion about a CT20B failing simply because it was made differently.

I'm probably wrong, but I'd like to know more. Feel free to post to the OC, I've done it before, and as long as it's part of an intellectual discussion I don't see why it should be a problem.

[Luni]

The 20b failure I have witnessed was a result of a fragged EGT probe tip.

The tip fragged, went through the turbo, and shattered the turbine. A steel wheel would have survived but it would have messed it up pretty damn good.

[47mr2's]

Ive had 3 of them fail on different cars. The oil seals usually go out on them. They aren't meant to run more than 17 psi. It doesn't have anything to do with oiling. The fact is they are not as durable as a USDM Ct26. Apparently there is a ct20 with a steel blade available on the later year st205 celica. I've never had one so I can't confirm but they are supposed to be good to 20 psi. I tend to think running 20 psi on a stock turbo is probably not the brightest thing to do but most people could care less what I think. That's why I could care less when they blow their motor.

[T@ZM@N!@C]

Im Very interested with this topic coz i have a 3rd gen mr2 also

The 7MGTE CT26 will bolt up to our exhaust manifold, but will not fit the down pipe. You would have to have a custom down pipe made. The turbo is single entry instead of twin entry, and has a slightly larger compressor wheel, with a better flowing turbine than the MR2 CT26

To ken for you what turbo will you recomend much better, the ct26 from 7mgte or the stock ct26 3sgte tnx

[kblake]

If you have the means to fabricate a custom down pipe, the 7MGTE CT26 is somewhat better than the 3SGTE CT26 in terms of peak power. IMO, unless you also upgrade the compressor side of the turbo off the 7M, it's not worth all the work to get it on there.

[T@ZM@N!@C]

Originally Posted by kblake

If you have the means to fabricate a custom down pipe, the 7MGTE CT26 is somewhat better than the 3SGTE CT26 in terms of peak power. IMO, unless you also upgrade the compressor side of the turbo off the 7M, it's not worth all the work to get it on there.

Thank you Ken

[mister3]

i have also seen and had MANY CT20b turbos with either blown seals, broken turbine wheels, etc..... must times if the seals are worn bad enough they become almost unrebuildable..... i think currently i have 3-4 sitting in the shop in pieces.....

also have had at least 10 JDM ceramic turbine CT26 with chipped turbine blades, wheels broken off, etc but usually they are more durable (i just get more gen2 clips in) over the long haul

i however have seen 1 and only 1 USDM turbo with steel turbine wheel break off.... was rather weird

[RageLtMan]

roflmao - i just read this whole thread from start to finish, you guys are nuts.

my $.02: in my quest for an MR2 i've driven a lot of them, enough to make my head spin. In the end, i got a 91 N/A with a 3rd gen done right. Here's why: the 2nd gen cars, even those with very high peak power, weren't nearly as smooth, or even as fast. Problem is that the owners who build their cars up for power are often the kind that like to brag, not drive. I'm a former owner of two porsches (924S and a 951) and i'm an avid fan of going for a long drive down some windy roads. The 2nd gen cars, with the great peak power are useless for that - by the time they build up all their tremendous boost your on the brakes so hard that it hurts. my 3rd gen, with nothing but intake and exhaust is perfect for this application as it delivers awesome acceleration right off the bat (and continues to pull hard in case i find that one long sweeper to stretch its legs).

The only stock 2nd gen i drove was a 91 and thoroughly dissapointing despite being in a great state of tune (i accidentally stepped out the tail presuming that it had an LSd and could stomach a fast turn - all my prior cars had LSDs). The common comment of "only 20hp" difference doesn't take into account the muscle car type powerband of the 3rd gen (yeah yeah, flame me, i know it doesn't make nearly as much, but power to weight ratio is the most important thing in a car - ask mcclaren or lotus about that).

Lastly, a buddy of mine bought an elise a while back and i had the privilege of driving it around with him. I believe that on paper the lotus is faster, but even though its a lotus modified 1,8 toyota engine, it doesn't deliver like the 3rd gen (or 2nd gen) by any means. However, that car gave me a hardon for mid engine setups with light weight and no BS (i am not a boxter fan, despite its great characteristics, only the S has enough power to do anything right and its still a lil heavy IMHO). My car has no power steering, no ABS, and no whiners allowed in the passengers seat - i'm a fan of old school sports cars to the point where i even considered a mk1 despite it looking like a deformed cheese wedge. Being lighter, the elise is definitely the better handler (then again, i need bigger tires, mine chirped in 3rd on the way home after buying it), but with a few chassis mods (strut bars!!!) and better rubber the MR would be on par, AND have more torque for a fraction of the cost.

While not being a toyota expert, i know a little bit about driving and the sheer tractability and response of the 3rd gen was what sold me - hell, i never thought i'd even drive one when i got in the market for an MR.

Questions:

what's a safe rev limit on the car? mine's stock far as i know which means 7500, i've heard of people running 9k though, how is that accomplished, and how bad of an idea is it? I dont plan to run high often, but i'd like the safety of a few thousand RPM in case i do something stupid and need the range to keep myself out of a tree.

chassis wise, AFAIK i'm still running th 91 rear end - i've seen more debate about the swap than i've read about religion. Any definitive answers? i wasn't about to kill car owners test driving their MRs so i never really got the full taste of the 93 setup , am i missing out? also, what's a good way to go for the strut braces?

Lastly what's the deal with this "other board?" What is it, why so taboo? If its got useful info for us, why can't newbies like me know about it? Someone PM me a link plz :-D
thx

[kblake]

Originally Posted by RageLtMan

my $.02: in my quest for an MR2 i've driven a lot of them, enough to make my head spin. In the end, i got a 91 N/A with a 3rd gen done right. Here's why: the 2nd gen cars, even those with very high peak power, weren't nearly as smooth, or even as fast. Problem is that the owners who build their cars up for power are often the kind that like to brag, not drive. I'm a former owner of two porsches (924S and a 951) and i'm an avid fan of going for a long drive down some windy roads. The 2nd gen cars, with the great peak power are useless for that - by the time they build up all their tremendous boost your on the brakes so hard that it hurts. my 3rd gen, with nothing but intake and exhaust is perfect for this application as it delivers awesome acceleration right off the bat (and continues to pull hard in case i find that one long sweeper to stretch its legs).

Sounds like you drove the wrong Gen 2s. Some people go for a big number, others for lots of area under the torque curve. MOST of the Gen 3s I've drive have been fairly laggy, not reaching 200RWTQ until 3800-4200 RPM, even with the stock turbo.

Here is an example of a Gen 2 built for area under the curve, road course, twisty roads, etc.:



That's 17PSI on pump gas, and it's neither laggy, nor peaky.

To answer your questions:

7500RPM is a good limit on a stock motor. If you want to rev higher, you will need valvetrain work, and lighter rods. Some balancing is a good idea too.

The 93+ rear suspension setup is far more stable at speed, and on the road course than the 91 setup. Several people who are seriously into tracking their cars have migrated to the late model rear suspension, with no regrets.


You shouldn't have any trouble finding the other mr2 board with a simple Google search for mr2 board. (hint: 4th result)

Ken

[MuMan]

This is a marathon thread!
I really can't see the issue between Gen2/Gen3 or USDM/JDM for that matter as any serious quest for performance means that most of the so called upgrades are going to finish up in the bin anyhow.
As for low mileage Gen3 imports, the wholesaler that I know, who buys them for export, says that most cars, that are knocked back on mileage turn up the following week with 42,000K on the addometer. Most of these are shipped to NZ for compliancing and distribution to the Southern Hemisphere, others are cut into clips and sold to dealers..few are smash vehicles.
Other than that, chances are that your low K 1/2 cut has spent most of it's life sitting in Tokyo traffic jams, idiling away for hours on end.
Just thought I'd mention it

[RageLtMan]

actually found it right after i posted, still dunno what to think of it.

I need a dyno plot, stat. I'm coming to think that there's something amiss here, either this thing is really in a great state of tune, or (more likely) the others i drove suck the large one full time - and are currently either being sold, or have been sold, to poor bastards like myself (as i almost bought 2 of em).

How can you tell if your ECU's been chipped/modified? I thought that wasn't done w/ Gen3s... all i can see here is that the BOV vents externally, the intake is a cone type seated low in the assembly, and that my cat resides in the rear trunk awaiting MA emission tests. That being said, that's from the few photos of 3rd gen engines i've seen, and god knows what's even stock around here

MuMan - my target is 300rwhp, nothing crazy. I want good response and driveability, with decent fuel economy, and a fun-to-drive factor of 10. That said, i wouldn't mind the bump in power just so as to eat the avg street contender in a quick pull if they're being belligerent (the SiR's 350z and US v8 crowd around here, oh, and those pesky subaru's too)

[Sang]

Originally Posted by RageLtMan

How can you tell if your ECU's been chipped/modified? I thought that wasn't done w/ Gen3s...)

Usually there will be a sticker or some form of identifying it on the case. Or you can open up the case and take a gander. But they have modified gen3 ECU's, it just costs more than doing it on a gen2 ECU...

[RageLtMan]

if i open up the ECU to look inside for mods - it'll be like my girlfriend popping my frunk to look for the spark plugs (women + cars = funny stuff, presuming you keep them from doing any damage): i wouldn't know a modified ECU from a stock one unless i know what to look for.

Also, where does one get chips for these things? How are they connected? (i'm a sys engineer in the 'real world' and can sodder, but would rather not risk roasting the brain without serious potential gain in performance/driveability/economy/etc and a good set of directions written for a grunt).

[Husler]

This thread maybe dead but for the record, Its alot of arrrogance with the gen3 community. I have nothing against gen3's but my big prolem is Ken is bring facts to the table and you guys just bash it which is plan stupid. I have my gen2 which has been pretty reliable until i turned the boost up and my fcon wasnt tunded for that and blew the rings. I opted for another gen2. why its cheaper can make the same power, it comes with 36,000km (i dont know the conversion in miles) and i got it for just 800 usd. so u gen3 guys out there before u go bashing on a gen2 and how the the gen3 is better the gen 2 has the same capabilities as the gen3 so it boils down to the same thing ken was talking about and u guys were ignoring your goals. because any smart person who is buying an engine to build would not buy a gen 3 which is almost a grand more expensive.

[Sang]

Lol at this thread. I wasn't "active" on this forum back in 2005...I thought this place and "MR2 Pride" was one in the same, heh. So I hardly came after signing up.

I tried reading through this thread...couldn't take much more when I got to somewhere on page 3. Then attempted to skim through the rest and got bored again at page 6

FWIW (and based on whatever I read in the first 6 pages) - I agree with Ken. I also feel that the gen2 head is great "design" regardless of having shim over buckets. I, personally, haven't seen a head spit out a shim. At least not on any "mild" builds with revs down near 8K rpms. I believe Aaron is only using valvesprigns on his 600whp beast still isn't he?

As far as the intake ports, i'll take those over the gen3 as well. Although, "larger", the TVIS (which some people seemed to have bashed in this thread) is a GREAT piece of equipment. With a gen3 head, you can ONLY have "small port" and "small runner" intake manifolds. Using a gen2 head, I would MUCH rather prefer to have stock runners using a modified plenum while actively controlling TVIS. Properly tuned TVIS makes for greater velocity at lower RPMS when the butterflies are close, then you get the full fledged "big port" volume when they are open on the top end.

It's a win-win situation, i don't know why more gen2 owners don't take advantage of it.

[Husler]

Sang I agree with you. You have to admit though if you spent 3500 on a gen3 clip and someone spent 1,500 on a gen2 engine harness and ecu and the remainder spend in mods and beats you in a q/m it would be lame. so those guys have to justify spending tha money. and one more point i have tried it you will never have enough power so if thats their argument i aint buying it. I have a few friends right now who are building gen3 swaps which is just plan dumb. just my 2 cents

[Ncturnal]

$1500 for a complete Gen 2 clip in good condition is an unrealistic price, and if you did find one at that price, that would be the exception, not the norm.

[Husler]

oh i am sorry i get my stuff straight from japan. you guys have to buy from a reseller. I have a gen2 3sgte i got for 800minus ecu with 25,000km how bout that. contacts. soon imma be speaking japanese

[Husler]

Originally Posted by Ncturnal

$1500 for a complete Gen 2 clip in good condition is an unrealistic price, and if you did find one at that price, that would be the exception, not the norm.

Also the gen 3 guys i can get all the parts for service for the gen3 engine