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Discussion Starter · #1 · (Edited)
I have an unopenned 2JZ turbo, non VVTI, fitted with a TO4R, fuel and management system, 3" exhaust, PWR fmic etc. I am running 116Sunoco fuel and would like to know the limits I should aim to stay within because at 25lbs boost it is still extremely happy and responding to everything I do to it. I am currently revvin to 7,200rpm as the std cams seem to fall away there. Can anyone tell me at what point the std rods etc fail. I have my own dyno so I am able to test and tune whatever reasonable suggestions people have here. Thanks in Advance.
Regards-Anthony
 

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ull blow the turbo before the motor, a to4r is a 67mm turbo that is only capable of around 700rwhp with a very large A/R... the stock 2jz can hold 700 rwhpreliably nething over 800 is pushing it.
 

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"Philzilla"
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Buznuts said:
I have an unopenned 2JZ turbo, non VVTI, fitted with a TO4R, fuel and management system, 3" exhaust, PWR fmic etc. I am running 116Sunoco fuel and would like to know the limits I should aim to stay within because at 25lbs boost it is still extremely happy and responding to everything I do to it. I am currently revvin to 7,200rpm as the std cams seem to fall away there. Can anyone tell me at what point the std rods etc fail. I have my own dyno so I am able to test and tune whatever reasonable suggestions people have here. Thanks in Advance.
Regards-Anthony
Your rods won't ever fail with a T04R (unless you start spraying a huge shot of nos, or run un-tuned, or run pump gas with high boost). As you've seen, the most you'll get with stock cams is about 700rwhp. Feel free to run 30psi of boost with confidence, with 116 octane fuel (even after you upgrade your cams). Be sure you're running at least 75# (785cc) injectors...

Please keep us informed, and post your dyno charts as you turn up the boost!
 

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Buznuts, where abouts are you in aus?

I have a gt42(74mm) and all the supporting mods(injectors/pump/ecu) and will be tuning it hopefully this week, but... the tuner says i shouldnt be boosting it to 30psi without upgrading bottom end(currently, my block/head is totaly stock).
Also, i will be running pump fuel + meth.
I was looking to run around 20psi on pump, and then 28psi or 30psi with the Meth squirting, any1 see a problem with this?( i run 850cc injectors)

Any1 keen on saying what boost limit would be applicable for such a fuel octane?
I also dont wanna damage the block yet, but woudl like to run close to the limits of my fuel octane, then upgrade later down the track...

Is that sunaco 116 equelent to teh c16?
 

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pwpanas said:
Your rods won't ever fail with a T04R (unless you start spraying a huge shot of nos, or run un-tuned, or run pump gas with high boost). As you've seen, the most you'll get with stock cams is about 700rwhp. Feel free to run 30psi of boost with confidence, with 116 octane fuel (even after you upgrade your cams). Be sure you're running at least 75# (785cc) injectors...

Please keep us informed, and post your dyno charts as you turn up the boost!
I'm with Phil, I don't foresee you breaking a rod with that turbo as long as your tune is in order and you have no mechanic failures elsewhere...

You run a better chance of eating a bearing (which could be attributed to a rod issue) by spinning to ungodly RPMs. But even that isn't much likely.
 

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Discussion Starter · #7 ·
Thanks for your input guys!
Yes I have 880cc injectors and am keeping the AFR to the 11.5 for now on the dyno and will aim for 11.9-12.2 at the top end of the track. At 25psi on a dyno dynamics dyno I am making 568rwhp. I am unsure of the limits of the standard engines as I am already way beyond impressed by its output. I am happy to feed more boost as the engine is showing no signs of breathing heavy or flexing in any way. I will keep my RPM to 7200 as I believe the standard cams are what is limiting it to that.
As I have told you my AFR, my timing is at 17deg at peak torque (5300rpm) and leads up to 20 deg by 7000rpm, I would be interested in some feedback on the direction I am on and whether I have much left in this set up.
Hey Mazman, I am in Melbourne and am the owner of Maztech and yes the Sunoco Extreme is the equvelent of C16 and have tested its integrity on engines that I know better and have found it to be just as good. I am playing with the 2JZ to learn more about them.
Regards-Anthony
 

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"Philzilla"
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Buznuts said:
Thanks for your input guys!
Yes I have 880cc injectors and am keeping the AFR to the 11.5 for now on the dyno and will aim for 11.9-12.2 at the top end of the track. At 25psi on a dyno dynamics dyno I am making 568rwhp. I am unsure of the limits of the standard engines as I am already way beyond impressed by its output. I am happy to feed more boost as the engine is showing no signs of breathing heavy or flexing in any way. I will keep my RPM to 7200 as I believe the standard cams are what is limiting it to that.
As I have told you my AFR, my timing is at 17deg at peak torque (5300rpm) and leads up to 20 deg by 7000rpm, I would be interested in some feedback on the direction I am on and whether I have much left in this set up.
Hey Mazman, I am in Melbourne and am the owner of Maztech and yes the Sunoco Extreme is the equvelent of C16 and have tested its integrity on engines that I know better and have found it to be just as good. I am playing with the 2JZ to learn more about them...
In theory, your current timing curve should be sufficient for 30psi with Sunoco Extreme. I'd advise you to raise boost slowly, about 2psi at a time, while logging you knock sensors on each run... Again, properly tuned, and with sufficient octane, the engine will take almost everything you can throw at it until about 37psi (yes 37psi!). At 37psi, some have reported the oem head bolts are insufficient and have gone to 1/2" ARP studs. Again, your oem rods are easily good to 850rwhp though a 6spd (1000hp at the crank), and the oem pistons are good to over 1000rwhp.
 

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pwpanas said:
Again, properly tuned, and with sufficient octane, the engine will take almost everything you can throw at it until about 37psi (yes 37psi!). At 37psi, some have reported the oem head bolts are insufficient and have gone to 1/2" ARP studs. .
Not entirely true....

it's a cylinder pressure issue, not so much a boost issue. You can run 37psi on a TO4R all day long without needing 1/2 inch head studs.

37psi on a 5591 misght contribute to a fair amount more cylinder pressure than the TO4R could.

All of that aside, it is 100% dependant on the tuning/timing, as the cylinder pressure spikes are what will kill the headgasket..... lunch time

Justin
 

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"Philzilla"
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justinn5 said:
...it's a cylinder pressure issue, not so much a boost issue. You can run 37psi on a TO4R all day long without needing 1/2 inch head studs.

37psi on a 5591 misght contribute to a fair amount more cylinder pressure than the TO4R could.

All of that aside, it is 100% dependant on the tuning/timing, as the cylinder pressure spikes are what will kill the headgasket...
Of course...37psi was only a conservative, and very rough guideline for Buznuts, since I doubt he's monitoring cylinder pressures. As I'm sure you also know, 37psi is starting to get beyond the efficiency range of a T04R and I doubt he's planning to run that much boost anyway. ...and again, count how many times I said "properly tuned" in my posts. :rolleyes: Besides, are you saying that in general, Mkiv Supra Turbo (apu) owners regularly running over 37psi generally shouldn't consider upgrading their head bolts/studs?
 

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pwpanas said:
Of course...37psi was only a conservative, and very rough guideline for Buznuts, since I doubt he's monitoring cylinder pressures. As I'm sure you also know, 37psi is starting to get beyond the efficiency range of a T04R and I doubt he's planning to run that much boost anyway. ...and again, count how many times I said "properly tuned" in my posts. :rolleyes: Besides, are you saying that in general, Mkiv Supra Turbo (apu) owners regularly running over 37psi generally shouldn't consider upgrading their head bolts/studs?
I saw you reference it back to back 3 times, so I figured I would stop any misnomers before they start(and before people start running 36.5 psii on stock assemblies). As you mentioned, properly tuned is the key.

Just to recap... It is not turbo pressure related, not 20psi, not 30 psi and not 40psi. The pressure that you have at the intake manifold tells you nothing of what's going on inside the engine, and how long the headgasket will last(if at all).

and of course, I am not saying that mkiv owners should NOT upgrade their head bolts..... where did you see that I even mentioned that?

A better question for him to raise would have been... how much torque can the stock rods handle? as the rod caps/bolts are the inevitable failure point on the 2JZ, all else being tuned. :)

Justin - Canadian by travel
 

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Discussion Starter · #12 ·
Thanks Justin and pwpanas, your comments and directions are greatly appreciatted!!!!
I like the concept of limiting output by torque which is usually directly relative to cylinder pressure, so I would like to hear your suggestions on what are the torque limits from your own experiences. Second to that do I assume that if modified camshafts move my cylinder pressures higher up the rpm range, will I be able to make my car faster and relatively safer by fitting bigger cams? i.e a higher rpm for peak torque.
I hope that my tuning is OK, but I am usually conservative with new projects. I use my torque/camspec theory on dyno comp cars here in Australia and usually find it successful on piston powered engines, however they are not unopenned engines from the manufacturer like this one.
Regards-Anthony Rodrigues
 

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Discussion Starter · #13 ·
Took the car to the track on friday night and with a badly slipping clutch managed a 10.88 at 128mph. I am fitting a better clutch and going back out again next week where I believe a low 10 should be on the cards. I think it has become my aim to run a 9 second pass on a completely unopenned engine. hat do you think my chances are?
Regards-Anthony
 

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It can be done, but I don't think its going to happen on that turbo. I am damn close and still pursuing the same goal with a larger turbo and stock internals(minus cams/springs and retainers).

DP
 

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Discussion Starter · #15 ·
Going from what people are suggesting, it sounds like I am fairly low on my boost at this stage. Should I raise the boost before trying more timing? The turbo is still responding to increases in boost pressure and responds best to leaner mixtures than increases in timing. Sounds like at least 30 p.s.i is hat most of you guys are running?
Regards-Anthony
Suprafied,
My car should be up to 400lb lighter than yours, so I hope this ill allo me to run marginally quicker, maybe just a little optimistic. Friday should tell as I have fitted a new clutch and am good to go again.
 

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"Philzilla"
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Buznuts said:
Going from what people are suggesting, it sounds like I am fairly low on my boost at this stage. Should I raise the boost before trying more timing? The turbo is still responding to increases in boost pressure and responds best to leaner mixtures than increases in timing....
Yes, imo.
Buznuts said:
...Sounds like at least 30 p.s.i is hat most of you guys are running?...
Ime, most with the oem shortblock limit boost to about 32psi (~2.2 bar), although 35psi and more has been run on the stock assembly with proper tuning and sufficient octane fuel. Also note that if you have a small exhaust housing on that T04R, more boost may not result in more horsepower.
 

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What boost levels would you reccomend with a fully built bottom end and L19 studs?
 

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Discussion Starter · #18 ·
Thanks PWPANAS!!!
I am running a .84 exhaust housing, I chose that because I believed the standard cams would run out at 7000rpm and this was originally built as a work vehicle so I wanted as early spool as possible. I run the 116 race fuel (Sunoco), so I believe I have enough octane. I will try 30psi at the track and see what results I achieve. I believe that it should be so close to a 9sec pass, I may make some performance influenced decisions that I would not normally make.
Dammn! This is fun.
Regards-Anthony
 

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"Philzilla"
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MissSupra said:
What boost levels would you reccomend with a fully built bottom end and L19 studs?
Carefully tuned, with appropriate timing & sufficient octane, you may be able to hit 45psi or more. As Justin stated however, you shouldn't use boost level as an absolute gauge, because (among other things) the precise amount of O2 flow at any given boost level is highly dependent on the size of the turbocharger. What you're really trying to do is to hit the 'magical' max cylinder pressure before the head & cylinder walls start to give way...and maximize the effectiveness of that pressure to drive the piston downwards at precisely the correct time. You're getting into an area where professional full-time tuners ... for pro race teams ... are still refining this upper 'edge' of tuning. In other words (fwiw), there isn't really a generally available, cut-and-dried answer as to exactly what the most effective boost level is for a given size of turbocharger, and the details of the tune to make it work near-optimally.
 

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Discussion Starter · #20 ·
Hey guys,
Clutch worked well and first pass ran [email protected] on friday night, now due to track safety rules I need roll cage, harnesses etc. Ran this easily with one lift on the throttle in the top end and @ 24 psi of boost. I had it tuned tu 29psi where it makes another 80rwhp so the engine is happy. I think the .84 rear housing is begining to become an issue, so I need to decide how far I want to go with this as it is my work car and my pro car is nearly ready to race again.
Regards-Anthony
 
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