Advice on rebuilding the VVTi 2JZ-GTE engine

[Guest pwpanas]

So every stock engine that has failed at 1000rwhp was due to det? They'll have needed to strip the engine to determine that? Horses bolted, gate closed type of thing?

When holes get blown through pistons, and/or chunks of metal are missing from the head, det is pretty obvious. It usually takes a nitrous system failure to bend the connecting rods.

 

We obviously have very different points of view. Perhaps I'm too much of a perfectionist; 'If something's worth doing...' and all that. If I followed your POV and just bolted on a turbo, every time I opened it up on a long pull it would always be in the back of my mind that something could let go. Some may want to take that gamble, me I'd rather make sure everything was in tip top working order from the beginning.

I have no problem with your perspective. The problem comes when guys start buying pistons and connecting rods *before* opening it up and inspecting it.

 

The only way you can fully check/verify the condition of an engine *BEFORE* rebuilding is to open it up and check all the tolerances. Compression & leak down tests will only tell you a limited amount about the condition of the engine.

I don't disagree. However, rebuilding for 800rwhp (6spd, US-spec dyno) or less is a total waste of $ for a 2jz-gte with good leakdown numbers, since the engine can handle at least 20% more than this. Edited January 1, 2011 by pwpanas (see edit history)

[Guest pwpanas]

He is referring to the difference in Dynos, the dynojet/ mustang dyno's they use seem to read a lot higher than the ones we use, this is backed up when i read talk of 700cc injectors being good for 700RWHP at 90% duty, we need 1000cc injectors to make 700RWHP on our dynos.

Interesting. I don't disagree that this could be a source for a US-UK difference of perspective on this topic. Agreed that 680cc injectors do make 650rwhp or so on our dynos (possibly running a bit higher-than-oem fuel pressure). Also, brand-new bone stock Mkiv TT's (running oem boost) dyno'd at closer to 300-320rwhp here. Any ideas for how we could reconcile this item so we're all 'speaking the same language'? Edited January 1, 2011 by pwpanas (see edit history)

[Guest pwpanas]

Facelift mounts are not as strong as pre facelift ones so if you plan on keeping it a while it may be worth upgrading to them, to swap you also need alloy cast bits as well as the mounts themselves.

What's a "facelift mount"? In the US, we use TRD engine mounts (solid urethane) as a replacement for oem.

[johnny g]

Interesting. I don't disagree that this could be a source for a US-UK difference of perspective on this topic. Agreed that 680cc injectors do make 650rwhp or so on our dynos. Also, brand-new bone stock Mkiv TT's (running oem boost) dyno'd at closer to 300-320rwhp here. Any ideas for how we could reconcile this item so we're all 'speaking the same language'?

 

That simply reinforces the belief that US-RWHP = UK-FWBHP

[JamieP]

Interesting. I don't disagree that this could be a source for a US-UK difference of perspective on this topic. Agreed that 680cc injectors do make 650rwhp or so on our dynos. Also, brand-new bone stock Mkiv TT's (running oem boost) dyno'd at closer to 300-320rwhp here. Any ideas for how we could reconcile this item so we're all 'speaking the same language'?

 

Yeah, 680cc injectors wont make anywhere near that power on our dynos, be lucky to get 500rwhp from them, Mkiv TT on stock boost would be not much more 220rwhp here, when i look at your RWHP all i do is pretend they are FWHP figures and it seems to work about right in my head.

Edited January 1, 2011 by JamieP (see edit history)

[JamieP]

What's a "facelift mount"? In the US, we use TRD engine mounts (solid urethane) as a replacement for oem.

 

TRD mounts are pre facelift style, i have them on mine, Facelift supras (1997-2002 cars) have smaller mounts.

[Guest pwpanas]

Yeah, 680cc injectors wont make anywhere near that power on our dynos, be lucky to get 500rwhp from them, Mkiv TT on stock boost would be not much more 220rwhp here, when i look at your RWHP all i do is pretend they are FWHP figures and it seems to work about right in my head.

Through a 6spd, that's a 15% difference, right? Perhaps we can, at least for the purposes of this discussion, agree that 15% is the US-UK dyno calibration factor? Edited January 1, 2011 by pwpanas (see edit history)

[Guest pwpanas]

TRD mounts are pre facelift style, i have them on mine, Facelift supras (1997-2002 cars) have smaller mounts.

Thank you for the info. Post-'98 info on the Mkiv Supra Turbo is scarce here in the US... If you don't mind a short digression from this thread topic, where can I find out more about all of these 'Facelift' changes (other than the well-known change to VVTi, of course)?

[JamieP]

Through a 6spd, that's a 15% difference, right?

 

6 speed, tbh we dont really do rwhp here, everyone on this forum always talks fwhp as that what most dynos owners give you, mine was 760rwhp= 894 fwhp.

[JamieP]

Thank you for the info. Post-'98 info on the Mkiv Supra Turbo is scarce here in the US... If you don't mind a short digression from this thread topic, where can I find out more about all of these 'Facelift' changes (other than the well-known change to VVTi, of course)?

 

Im not sure if there is a link anywhere, few differences off the top of my head, there is other things i have forgot im sure.

 

VVTI on the 98 cars

V161 gearbox or triptronic

smaller diff

smaller rad

Dash inserts and interior is different

They have different headlights/tail lights/ indicators.

Front bumper is slightly different.

Edited January 1, 2011 by JamieP (see edit history)

[Guest pwpanas]

at the first reply Nic, i tried to be diplomatic;)

And well replied to the rest, i suspect a somewhat blinkered attitude to the art of tuning.

Hey - I resent that remark! ...seriously though, perhaps the source of confusion has been this US-UK dyno calibration conversion factor. Please trust I'm well aware that a narrow-minded approach to tuning leads to unexpected failures. On the other hand, I do consider fixing what isn't broken and/or replacing oem parts perfectly capable of handling the goal rwhp level to be both terribly wasteful and needlessly introducing changes that in themselves may be potential sources of failure. Otoh, we've disassembled, inspected, and reassembled several brand-new 2jz-gte shortblocks to ensure that, among other things, that all oil passages are properly drilled. In the US, Toyota had a bad batch of 2JZ-GTEs with improperly drilled oil passages. Edited January 1, 2011 by pwpanas (see edit history)

[JamieP]

Out of interest what rpm limit do you guys regard as safe for a big power stock engine?

[Morpheus]

For those that don't know, the issue with rods is bolt stretch and the resultant cap walk or even cap stretch at anything above about 8000 rpm in your average engine. The stress of pulling the piston back down from TDC when drawing in a fresh charge is at maximum then, as the rod isn't under compression. The inertia and drag of the piston/rings puts huge stress on the rod at high speed, hence drag cars using lightweight pistons for high rpm.

 

Horsepower won't in itself bend rods as maximum torque is by definition, only going to be generated at high revolutions so the compression forces on the rods will be spread relatively evenly between them. Severe detonation and hydraulic lock are the only ways to bend them unless a cap bolt breaks at high rev's, leaving the piston halfway down the cylinder and the crank hits it next time round, throwing the rod through the block.

 

Therefore, we know that 'some' rods can handle 8k all day long and as much HP as you like, if mapped and fuelled properly.

 

Is there a definitive answer as to how much stock rpm 2JZ rods can handle safely, as a rule? They won't all be identical. I was told that Toyota never said what alloy was even used. Bolts are the main issue though.

Edited January 1, 2011 by Morpheus (see edit history)

[Bailey.]

Yeah, when i look at your RWHP all i do is pretend they are FWHP figures and it seems to work about right in my head.

 

exactly the same, 6765's making 800whp, just not possible, yes 800 fwhp, just, but not whp.

[Guest pwpanas]

6 speed, tbh we dont really do rwhp here, everyone on this forum always talks fwhp as that what most dynos owners give you, mine was 760rwhp= 894 fwhp.

Ok then...18%? 20%? I'd ask that we do agree on a number.

 

Just curious - was your 10.5@138 on slicks or at least drag radials? ...front swaybar disconnected? Even if 760rwhp was US-dyno-spec, I believe that you should be in the 9s with that hp level.

[Morpheus]

Out of interest what rpm limit do you guys regard as safe for a big power stock engine?

 

Beat me to it!

[Bailey.]

Out of interest what rpm limit do you guys regard as safe for a big power stock engine?

 

I think im going to try 7500rpm on stock engine jamie, just for the cause. lol. will use uprated valve springs and phr oil pump though.

 

generally with the mods above they will say 8k,?

[Guest pwpanas]

Out of interest what rpm limit do you guys regard as safe for a big power stock engine?

The oem 2jz-gte can take 9k everywhere except the oem valve springs (at high boost and high rpms the shims will pop out). Since big power requires aftermarket cams anyway, we typically upgrade the head with dual valve springs and titanium retainers....which in turn has lead to timing belt tensioner bracket failures...which we typically upgrade too. Note: I'm not expericenced with the VVTi head, so there may be parts of that system that can't take 9k+ either... Edited January 1, 2011 by pwpanas (see edit history)

[JamieP]

Ok then...18%? 20%? I'd ask that we do agree on a number.

 

Just curious - was your 10.5@138 on slicks or at least drag radials? ...front swaybar disconnected? Even if 760rwhp was US-dyno-spec, I believe that you should be in the 9s with that hp level.

 

Its near impossible to agree on a number, like i say, at a guess call our fwhp the same as your rwhp and i dont think it will be far out.

 

I never had 760whp when i did that, maybe 700, i was on 17" volks with drag radials, 1.8 60ft, id hope to be in the 9's next time i have a go with my 15" welds i have now.

[Guest pwpanas]

For those that don't know, the issue with rods is bolt stretch and the resultant cap walk or even cap stretch at anything above about 8000 rpm in your average engine. The stress of pulling the piston back down from TDC when drawing in a fresh charge is at maximum then, as the rod isn't under compression.

 

Horsepower won't in itself bend rods as maximum torque is by definition, only going to be generated at high revolutions so the compression forces on the rods will be spread relatively evenly between them. Severe detonation is the only way to bend them unless a cap bolt breaks at high rev's, leaving the piston halfway down the cylinder and the crank hits it next time round, throwing the rod through the block.

 

Therefore, we know that 'some' rods can handle 8k all day long and as much HP as you like, if mapped and fuelled properly.

 

Is there a definitive answer as to how much stock rpm 2JZ rods can handle safely, as a rule? They won't all be identical. I was told that Toyota never said what alloy was even used. Bolts are the main issue though.

Don't disagree with anything except the 8k. Even at 10K it's doubtful the oem 2jz-gte rod bolts or caps would fail.

[Morpheus]

Thank you for the info. Post-'98 info on the Mkiv Supra Turbo is scarce here in the US... If you don't mind a short digression from this thread topic, where can I find out more about all of these 'Facelift' changes (other than the well-known change to VVTi, of course)?

 

Here you go. Pdf links are in the first post.

 

http://www.mkivsupra.net/vbb/showthread.php?59334-Supra-Guide-and-Model-Differences-Chart/page3

[JamieP]

The oem 2jz-gte can take 9k everywhere except the oem valve springs (at high boost and high rpms the shims will pop out). Since big power requires aftermarket cams anyway, we typically upgrade the head with dual valve springs and titanium retainers....which in turn has lead to timing belt tensioner bracket failures...which we typically upgrade too.

 

Blimey, nobody has ever dared rev a stock engine or built engine so high over here i dont think, i rev mine to 8100rpm, might raise that now, i have all the mods you talk of including shimless buckets.

[Bailey.]

Don't disagree with anything except the 8k. Even at 10K it's doubtful the oem 2jz-gte rod bolts or caps would fail.

 

serious, even in the states i havent notice many stock block singles running over or 8k rpm?????

[Guest pwpanas]

serious, even in the states i havent notice many stock block singles running over or 8k rpm?????

Agreed if we're statistically counting, but it depends on the application and the desire for longevity. It's always a balance between the customer's/owner's desire for optimal performance (for a given application) vs. his desire for the engine to run another 50K miles without a rebuild. Most tuners do tend to set the rpm only as high as is required to take advantage of the single turbo that is installed. Of course, a 67mm turbo doesn't need as much rpm as an 88mm turbo to get well through the hp peak. On the other hand, pro drag teams (eg. Titan Motorsports) do run well beyond 10K rpm for an entire season without an rpm-related failure. Edited January 1, 2011 by pwpanas (see edit history)

[Morpheus]

Don't disagree with anything except the 8k. Even at 10K it's doubtful the oem 2jz-gte rod bolts or caps would fail.

 

Cool, I said your average engine like the V8's etc. as I've been rebuilding my Typhoon V6 and learning all this in the process. Excellent post on the shims btw. I'll be replacing my timing belt soon and was wondering if it's worth upgrading the tensioner bracket while I'm at it? Seen pics of broken ones and sounds like good insurance. Would this be a case of replacing something perfectly good except in a highly modded engine? Using a Gates racing belt, the blue one.