Supra Forums banner
1 - 20 of 24 Posts

·
Drive Hard
Joined
·
640 Posts
Discussion Starter · #1 ·
HI...i'm new of this forum...my name is Paolo and i live in Rome, Italy.
i bought this week a 93 Supra Mk4 TT, but it has 170.000 km....
I think to change pistons with a forged set, but which i have to buy?
CP? J&E? Greddy?
I need 800hp max.....
please help me :hug:
 

·
Undefinable
Joined
·
968 Posts
DevilSupra said:
HI...i'm new of this forum...my name is Paolo and i live in Rome, Italy.
i bought this week a 93 Supra Mk4 TT, but it has 170.000 km....
I think to change pistons with a forged set, but which i have to buy?
CP? J&E? Greddy?
I need 800hp max.....
please help me :hug:
The MkIV turbo came from the factory with forged internals. There is no need to replace them unless the car was abused or you just feel like doing a total rebuild of the motor.
 

·
Drive Hard
Joined
·
640 Posts
Discussion Starter · #4 ·
Hua said:
The pistons are not the weak part, the rods are.
the rods are subjected to wear and tear? i didn't know that......
 

·
Registered
Joined
·
1,199 Posts
the condition of your block will tell you if you need to replace anything. do a compression test and check to see if the number across all 6 cylinders are within 5 +/- of each other. if not, you may want to look into replacing your shortblock from toyota (they can be had pretty cheap...around 1900-2200 plus shipping). our blocks have seen 250,000 miles or more without having the be replaced, but that all depends on the previous owners maintence, and how well they took care of the car and whether or not they abused it. the shortblock in the 2jz is good for a ton of power....everyone has different opinions as to how much power it can handle, but i think the general consensus is that 800rwhp is the safe limit on them. however, the amount of power you put through it on the dyno is much different than putting that same amount of power on the strip/street. the car (engine) is subject to much more stress on the drag strip and street, so if you plan on dragging or racing the car often, id suggest just building the bottom end with a little more beefy components. as mentioned above, the stock pistons are the stronger part of the motor, and can handle a ton of power thrown at them. however, the stock rods seem to be the weak link in our motors. so replacing the rods would be the first task, and replacing the pistons is up to you. i am in the middle of having my block built and i went ahead and opted to have CP pistons put in, along with crower rods, arp hardware, and clevite bearings.

pistons, i would choose from cp, je, or weisco. rods are a bit more tough to pick from as everyone says one is better than the other. i would have liked to get carillos, but i think they would have been overkill for me, as i never plan on pushing more than 950rwhp (850rwhp is my ultimate goal). but there are several threads which you can search and find good info about all the rods available for our motors such as this one ...
http://supraforums.com/forum/showthread.php?t=118761&highlight=pauter+carillo+crower

if you do decide to build the bottom end, id look into replacing the bearings with clevites. as well as throwing in the arp hardware.

if you do decide to build the bottom end, your going to be looking at around $800 + parts (overall price depends on what rods/pistons/bearings you select). hope this helps.
 

·
Drive Hard
Joined
·
640 Posts
Discussion Starter · #6 ·
i3oca said:
the condition of your block will tell you if you need to replace anything. do a compression test and check to see if the number across all 6 cylinders are within 5 +/- of each other. if not, you may want to look into replacing your shortblock from toyota (they can be had pretty cheap...around 1900-2200 plus shipping). our blocks have seen 250,000 miles or more without having the be replaced, but that all depends on the previous owners maintence, and how well they took care of the car and whether or not they abused it. the shortblock in the 2jz is good for a ton of power....everyone has different opinions as to how much power it can handle, but i think the general consensus is that 800rwhp is the safe limit on them. however, the amount of power you put through it on the dyno is much different than putting that same amount of power on the strip/street. the car (engine) is subject to much more stress on the drag strip and street, so if you plan on dragging or racing the car often, id suggest just building the bottom end with a little more beefy components. as mentioned above, the stock pistons are the stronger part of the motor, and can handle a ton of power thrown at them. however, the stock rods seem to be the weak link in our motors. so replacing the rods would be the first task, and replacing the pistons is up to you. i am in the middle of having my block built and i went ahead and opted to have CP pistons put in, along with crower rods, arp hardware, and clevite bearings.

pistons, i would choose from cp, je, or weisco. rods are a bit more tough to pick from as everyone says one is better than the other. i would have liked to get carillos, but i think they would have been overkill for me, as i never plan on pushing more than 950rwhp (850rwhp is my ultimate goal). but there are several threads which you can search and find good info about all the rods available for our motors such as this one ...
http://supraforums.com/forum/showthread.php?t=118761&highlight=pauter+carillo+crower

if you do decide to build the bottom end, id look into replacing the bearings with clevites. as well as throwing in the arp hardware.

if you do decide to build the bottom end, your going to be looking at around $800 + parts (overall price depends on what rods/pistons/bearings you select). hope this helps.
you are my angel.... :) ....this is a great guide...
thank you so much
i think to built the bottom end first for engine's reliability...so now i order rods kit,arp hardware and i do a compression test
 

·
Registered
Joined
·
2,180 Posts
Ummm, the supra comes stock with forged pistons and the rods are the weak point? According to mkiv.com, the supra's RODS are forged, I wasn't aware the PISTONS were forged, and what makes the rods the weak point if they're forged?
 

·
Registered
Joined
·
4,912 Posts
i thought the pistons were cast and the rods and crank were forged. so how much power can you run on the stock rods? could you do a aftermarker rod w/ toyota piston combo?
 

·
Registered
Joined
·
904 Posts
supralover93 said:
i thought the pistons were cast and the rods and crank were forged. so how much power can you run on the stock rods? could you do a aftermarker rod w/ toyota piston combo?
You can do an aftermarket rod with a stock piston combo provided you went with a new short block. I know of several high power Supras running this combo. I opted for carrillo rods, cp pistons, and my tuner chose clevite bearings over factory toyota bearings,however, there are many who have had success with the toyota bearings. Even more important for our Italian friend is finding a machine shop capable of performing the engine rebuild. Or they may choose to buy from a U.S. tuner.
 

·
Registered
Joined
·
659 Posts
DevilSupra: that's nice to have someone else in italy with a MKIV :)
To answer to your engine questions: i3oca is certainly right, but i recall that several people put over 900rwhp on the dyno using completely stock internals with a T88H kit. This does not mean you'll be able to do the same, and a deep and accurate test session on your engine made by a good shop is the best chiuche. Once you've done compression test and see all your numbers are ok i believe that you may start on your 800whp kit without worrying too much about it. Pistons/rods/crankshaft are not so weak. they definetely are not :) Of course changing piston/rods (and maybe blueprinting cranckshaft) is not bad, but i feel it's a step that can be easily avoided at first. Rods may fail under high power, that's true, but they have a very reasonable safety margin at the power level you want to achieve. At first, you'd be better to upgrade your valvetrain: you won't be able to get that power at less than 7500rpm, and it is not very safe to run the stock valvetrain costantly at those revs ;) so a good set of crower/HKS camshafts, a set of double springs and maybe some slightly oversized valves (+1mm ferrea) would be a deal.

ciao
Nico
 

·
Banned
Joined
·
4,144 Posts
The stock pistons will last close to over 900 rwhp and give little issue...

Hua was correct in that the stock rods are the weak point....

The stock pistons are cast, yet the stock rods are forged......

In your compression check, all cylinders should be as even as possible, but by Toyota manual, be no more than 14psi off from each other....

Building the motor is like building a pizza, everyone does it there way. But if you are goign to break the seal, so to speak, consider keeping the stock pistons, a set a H-beam rods (Carillo, Eagle, ect..), and upgraded bearings. That will give you 800 rwhp all damn day assuming the tune is right.

Eric
 

·
Registered
Joined
·
27 Posts
Why do stock rods have casting lines dow the side of them,or what look like big fat casting lines?

I dont know for sure, but they look like very good castings .. not forged??

The crank is cast too, or are the counter wieghts just cast, and the journals forged?

:dunno: :freak:
 

·
NFA Pimp
Joined
·
2,734 Posts
ALL CONNECTING RODS ARE FORGED, IN EVERY CAR YOU SEE ON THE ROAD TODAY!!! The "casting" lines you see down the connecting rod is from when the dye is slamming down on the hot molton metal.
 

·
Registered
Joined
·
13,581 Posts
"ALL CONNECTING RODS ARE FORGED, IN EVERY CAR YOU SEE ON THE ROAD TODAY!!! "

I don't agree with that. For cost reasons, not performance, many cars today are use powdered metal rods and just because you slam a handful of powder into a solid part, I wouldn't call that a forged rod. I think there is still a clear distiction between forged and compressed/sintered powdered metal.
 
G

·
G said:
ALL CONNECTING RODS ARE FORGED, IN EVERY CAR YOU SEE ON THE ROAD TODAY!!! The "casting" lines you see down the connecting rod is from when the dye is slamming down on the hot molton metal.

no they are not...
i can speak for ford. 03 and 04 cobras and SVT focus are THE ONLY cars with forged rods from the factory...EVERYTHING ELSE that we make is hyperutetic (powdered) rods and pistons
 

·
Drive Hard
Joined
·
640 Posts
Discussion Starter · #17 ·
Cosmic Chaos said:
DevilSupra: that's nice to have someone else in italy with a MKIV :)
To answer to your engine questions: i3oca is certainly right, but i recall that several people put over 900rwhp on the dyno using completely stock internals with a T88H kit. This does not mean you'll be able to do the same, and a deep and accurate test session on your engine made by a good shop is the best chiuche. Once you've done compression test and see all your numbers are ok i believe that you may start on your 800whp kit without worrying too much about it. Pistons/rods/crankshaft are not so weak. they definetely are not :) Of course changing piston/rods (and maybe blueprinting cranckshaft) is not bad, but i feel it's a step that can be easily avoided at first. Rods may fail under high power, that's true, but they have a very reasonable safety margin at the power level you want to achieve. At first, you'd be better to upgrade your valvetrain: you won't be able to get that power at less than 7500rpm, and it is not very safe to run the stock valvetrain costantly at those revs ;) so a good set of crower/HKS camshafts, a set of double springs and maybe some slightly oversized valves (+1mm ferrea) would be a deal.

ciao
Nico
i'm the first in italy with a tuned mkiv!! :bigthumb: it's a great satisfaction. When i can i post some photos...

where i can buy pistons and rods? mvpmotorsport? or there's some cheaper?
thanks to all
 

·
Real Girl Thread FTW!
Joined
·
4,626 Posts
Welcome, is nice to hear we are reprsenting in Europe :bigthumb:
Like all the othe mebers say, is not necessary to do anything unless the motor is hurt. With the right combination you can make as much as 900+ Hp on a stock block. :stickpoke
Don't spend the money in the wrong place at the wrong time :dunno: ....
Do a compression test, fuel filter change, nice set of plugs, etc, etc, etc....
Enjoy the new ride :sadance:
 

·
Registered
Joined
·
2,180 Posts
First I hear that "the MKIV came from the factory with forged internals" in post #2, and forged internals means forged pistons. Then I hear that the stock pistons are cast and the stock rods forged in posts #9 and #12. WHAT IS FORGED AND WHAT IS CAST ON OUR CARS? I'm going to assume posts #9 and #12 are correct and that the rods and crank are forged and the pistons are cast.

If the pistons are cast and are not forged, how is it that the cast pistons are stronger than the forged rods? I thought forging created a stronger product than casting? At what power level is it necessary to replace the stock pistons with a CP or JE forged piston?
 

·
I'm back!
Joined
·
6,712 Posts
Regarding the 2JZ-GE and 2JZ-GTE:

The 2JZ-GE engine is similar in many respects to the factory turbo, even down to the vestigial engine block fittings for turbo oiling, oil return, and coolant plumbing. Both engines use pressure-cast pistons, although the Turbo has more sophisticated piston-oil-cooling and wrist-pin lubrication. Obviously the 2JZ-GE uses much higher compression pistons.

crankshaft & torsional damper

the forged steel crankshaft incorporates twelve counterweights and seven main journals; the main and rod journals are induction hardened. replaceable aluminum alloy main bearings are used.

a dual mode torsional damper is fitted to the front of the crankshaft. this is NOT an external balancer, as the crankshaft is fully balanced, rather it dampens both the axial twisting couples produced by the firing pulses, and the radial bending moment from the accessory drive belt.


Pistons and Connecting Rods

the stock supra pistons are as advanced a design as any aftermarket piston, and the rods are already forged. the stock reciprocating assembly "can" hang together just fine up to 8000-8500 rpm (although we're rev limited to 6900-7200) and can produce insane power levels. however, to be fair to the aftermarket, there are some weight savings and strength increases to be gained with aftermarket rods and pistons, but these become advantageous only when the engine is being prepped as a full race engine.
 
1 - 20 of 24 Posts
Top