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Location:
UK
Registered:
May 2002
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1JZ Y pipe (again)
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Wed, 03 July 2002 16:19
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Hi all, having my turbos rebuilt (steel internals, 360 deg bearing etc) and thought id take the oppurtunity to get rid of the Y pipe. i've read about the twin pipes from premier exhausts but seeing as im in the UK and dont want top spend megabucks i might get something made up over here. I've seen the pic below and was looking at something similar. Is the design in the pic crap? Would it have much benefit? The car is a JZA70.
cheers
adi
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 00:18
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I think what you have would be an improvment , but no where near as good as some other designs around.
I am about to get mine done on monday , in twin 3 inch mandrels and they will continue as twins for as far as possible,maybe even right down to the cat. the idea being to straighten out the gas flow as much as possible.
You may still get some disturbance at the junction there.
Who was that Kiwi, who was offering $100 for the first person to post up before and after dyno charts.
there will be two separate cars with new twin pipes to post before and after results by mid newxt week.
Both of us will be a the coming dyno day.
That'll be $100 australian too !! Thankyou
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Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 01:00
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I wouldn't rely on that $100. I am also making my own twin pipes and I look to be leading the forward pipe down and out and the aft turbo up, back and down. Both will be something like 30-40cm long as I think that given the restriction in turbo size, that extra gain going all th way to the cats will reap nothing. I think as long as that dang junction is pegged, you'll fix most of the restriction.
God I hate insurance companies, those turbos would be gone long ago otherwise.
The pipes pictured look very cheap and a whole lot easier to make than the longer ones.
Can we contact the person with this mod?
Pete
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Location:
UK
Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 09:57
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You can contact him but he's based in the US. He had the pipe made up as a one off but the guy who did it still has the jig/measurements etc to knock some more up, and will do so if enough people want them at roughly $300 US dollars.
I was going to simply get a machine shop to knock something up for me, as i'll be able to give them the old Y pipe as a template. Prob much cheaper than buying one pre made.
check http://groups.yahoo.com/group/MKIIIJZA70/
if yuo want to find out more.
adi
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Location:
Sydney
Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 12:15
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I fitted the Y-pipes about 4 weeks ago but made too many other changes at the same time to pinpoint it's actual individual effectiveness. At least the capacity to flow is greater now to assist all other and future mods.
Had to modify Brendan's pipes considerably though to clear oil/water feed/return pipes and rear turbo support bracket.
O2 sensor rellocation was fun as well - wires are considerably stretched now, so extending is on the cards now when I can find matching plugs.
Still keen to see someone's before and after dyno graphs of the change at stock boost and ellevated boost.
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I supported Toymods
Location:
Perth WA
Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 13:07
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I have my doubts that you would be able to tell the benefits of the twin pipes with the standard car at standard boost. There are just too many other power constraints, like the intercooler, fuel mapping etc. You may be able to measure changes in the power CURVES on dyno, but I suspect the real gains will be when you have a few mods on board.
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Location:
UK
Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 13:31
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The plan is to run at 1bar for a while on the new turbo's (which will take it better than the stock ones). Therefore with the increased boost i need/want to get rid of the restrictive Y pipe.
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I supported Toymods
Location:
Perth WA
Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 13:37
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If the new pipes work as well as you hope, you should hopefully get cooler exhaust gas temps (? - correct me if I'm wrong). I'd like to see how they go as the faster gas flow should go some way reducing the lag you would get from replacing ceramic turbines with the steel (assuming the same turbine design but heavier mass).
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Location:
UK
Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 17:40
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Yep to be honest that was my main concern with fitting the steel internals. Hopefully as you say the increased flow will make up for the lag.
I'll post the results in a couple of weeks.
adi
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Registered:
June 2002
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 20:49
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Hi-those are actually my pipes. I think you are on the mk111jza70 list right? There are a few reasons the pipe was made like that. The first one is I was in the middle of doing the engine swap into my US spec ma70 supra. Custom fabraction and measurements really couldn't be made at the time. The other is I had already bought an HKS downpipe and didn't want to hack it all up. That piece is basicly just a copy of the stock unit-everything mounts the same. Putting the two side by side, you'll see there is quite an improvement. I never once drove the car with the stock piece on, so I can't comment on the differece. We never really intended to sell the pipes, but he can make more of them-he did have to make a jig up so he can make another one.The car made 327.1 rwhp and 320.6 TQ two days ago. All at 15psi-still need to get around fuel cut. Other mods to the car are jap spec 2jz 440's, mkiv fuel pump,hks down pipe,no cat,apexi catback,apexi intake,greddy boost controller and apexi AFC.These #'s were all made on a US dyno-I guess you guys use a different type. Here is a pic of the pipe fitted:
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Location:
UK
Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 22:02
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Yep, that was me...
Yep itd be far easier for me to make up one similar over here than ordering one from elsewhere. Hence the pic and question. To be honest id completely forgotten about the lambda sensor fitting in it so its a good job you posted the pic.
The plan is to take the existing Y pipe to a few people and see if they can make a unit similar to yours. Lets face it anythings gotta be better than the stock unit !
cheers
adi
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Registered:
June 2002
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Re: 1JZ Y pipe (again)
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Thu, 04 July 2002 22:08
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That would likely be your best option. it shouldn't be hard at all. Thats what I did, gave my friend the pipe and had him make up one....
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Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Fri, 12 July 2002 09:40
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The $100 offer was from me,and it still stands,despite Celicamad calling me a "tosser" and a "dickhead" and saying my twin pipes were obviously poorly made(by the way ,they are equal/superior in craftsmanship to anything I have seen on the net so far)and it was implied that I wouldn't pay,and he said the $100 wouldn't even pay for the dyno.
I never thought that it was my responsibility to pay for someone else's dyno.
I did the mod,my 'before and after'(and several subsequent) dyno runs were inconclusive,so I offered the $50 for the first person to post a B4/after dyno of the twin pipe mod,with no other changes to complicate the test.The offer excluded the 3-4 of us who already had the pipes installed.Strangely,silence followed.I increased the offer to $100(AUST) cash several months ago,and this is the first I have heard since.The money is waiting.I want to see other peoples results,given that mine conflict with Celicamad's.
It's a simple offer,I never realised it would cause people to spit the dummy.
Post those dyno graphs,1JZ men.
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Re: 1JZ Y pipe (again)
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Mon, 15 July 2002 08:09
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Got my pipes done last week, and I'm confident of a reasonable increase in mid and top end.
I tried something different with the rest of my exhaust as well.
i had a half twin sytem before and its now nearly all twin .
from the turbo's there is 2 3/4 inch pipes, in to twin 2 1/2 inch cats, twin 2 1/2 inch straight through mufflers, and a join into a 3 1/2 inch pipe behind the diff. Will soon have a Jun bl 3 1/2 inch muffler to shut it up, this system redefines loud !!!
I'l lhave it back on the dyno very soon, though my dyno figures will be slightly out as on the dyno day ( I found out when we pulled the plumbing off) I had a hole in my intercooler plumbing, (the plastic bit) a couple of mm across. So that might explain my low figure and detonation on the dyno day, as my evc flogged crap outa my turbos to make the 1 bar i was asking of them.
anyway results soon.
Matt
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Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Tue, 16 July 2002 02:32
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Hi Gents,
Yep, I'm also doing my pipes next week, however I'll keep my 3.0" system from the joint back and see what happens.
Forgot the last post above me, but what sort of pipes dod you use, what size and length before join.
OK, who should I order from and how much coin. I want to order this week. Also, how much will my curent 2.75" high flow cat restrict me in my 3.0" system, also same qn for a 3.0" resonator.
Anyone got a large intercooler for sale for a JZA70?
Pete
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Location:
UK
Registered:
July 2002
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Re: 1JZ Y pipe (again)
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Thu, 18 July 2002 22:33
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Hi, Oz-bods.
I normally post on the LSOC.
These Y-pipes are more complex in their operation than you would think, they are designed to provide a good restriction at the top end of the rev range and not impede flow low down too much but just enough to provide good torque.
The only design that works is the half helix design, just clearing its throat will screw the low down torque and you feel that more than the top end benefit.
To use the simple designs I've seen you would need to have a huge increase in top end so that the 'trickle down' effect just makes up for the low end failings, to obtain the torque and the top end you need distance references for torque generation, the distance to the turbine×the flow restriction from the turbine (around 0.7)peak torque ristriction point (around 2000rpm) as a factor of flow design rate (Froud number 1.6)
85×0.7×2(k)×1.6 around 190mm from the valve head or 95mm for each 1000rpm step in the 'boost point'.
Simple really.
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Location:
Sydney
Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Sat, 20 July 2002 12:11
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Welcome aboard Iain. 
Now you've confused the f@#k out of most of us.
Remeber the KISS principle when explaing things to us OZ-bods. 
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Location:
Sydney
Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Sat, 20 July 2002 12:14
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Dont forget that you have turbines inside the exhaust to help the back pressure.(more back pressure at lower revs, less at higher, as they start to spin faster)
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Location:
UK
Registered:
July 2002
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Re: 1JZ Y pipe (again)
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Sat, 20 July 2002 17:26
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#Dont forget that you have turbines inside the exhaust to help the back pressure.(more back pressure at lower revs, less at higher, as they start to spin faster)# That is the '0.7' part of the formula.
Torque generation low down needs heat, hence the restriction, just making the gas exit quickly will just mean the car is weak low down, ever noticed when the engine is cold (I know you don't really have proper Winters out there) even with elevated revs the engine can stall? Well that is a cold engine, the amount of torque generated is very low, well just up the temp and then look at it that way, if the engine is restricted it gets hot and full generation of torque is made.
This is a balancing act, if you run at 14psi then you need a little less restriction not an excessive amount.
The formula above allows you to do this, without changing cams then I think about 2300rpm is about right. that means the restriction or junction should be 217mm and shoulb quite abrupt, flowed but abrupt.
[Updated on: Sat, 20 July 2002 17:29]
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Re: 1JZ Y pipe (again)
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Sun, 21 July 2002 04:43
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What is this length you calculated.
the length from where to where ??
I am considering putting a v8 style X pipe into my system, though my exhaust dude reckons that gtr's make more torque with a twin system all the way back and so should mine.
I am not convinced.
Matt
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Location:
UK
Registered:
July 2002
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Re: 1JZ Y pipe (again)
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Sun, 21 July 2002 10:21
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The distance from the start of the Turbine, the point where it starts to turn it, to the point where the pulses of gas conjoin.
The Cross-pipe should be fitted just before the rear wheels and should be a pipe at right angles to the pipework not forming an 'X' but forming an 'H' the 2 longer 'legs' of the 'H' being the 2 main pipes that lead to the rear 'boxes, the cross pipe, the new pipe is parallel with the rear axle line like the rung of a ladder. The position is not too critical but at least 18" from any 'muffler'.
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Re: 1JZ Y pipe (again)
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Sun, 21 July 2002 22:25
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I have a y section join, just behind the diff. which now goes into a 3 inch muffler.
from the turbo's back it goes into twin cats and then twin 2 1/2 inch straight through mufflers, very small, before the diff.
DO you think there is still an advantage to adding a cross pipe after the cats and small mufflers or before them ??
I could possibly do the join between them also.
Whattaya reckon ??
Matt
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Re: 1JZ Y pipe (again)
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Sun, 28 July 2002 11:03
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Well any concerns I had about the effectivenes of the twin pipes has vanished.
Today I went out to Celicamad's place and run the car on the Dyno plus again, and recorded a clear 35 rwhp gain.
It produced a hold hp of 287 (291 peak) rwhp @ 14psi, dropping to figures in the 270's after a number of runs, idle intake temps were now over 40 deg (let alone on boost), and heat sink set in. These runs were done mid afternoon too, not in the middle of the night with low ambient temps , it was warm in newcastle today.
Also recorded a 5.36 second 0-100 time with two big guys in the car, Toy77(85kg) and me (94kg). So you can make your own speculations about how much faster It would be with only me in the car.
This is nearly 0.5 of a second faster than my previous best( with 2 up).
Matt
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Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Mon, 29 July 2002 01:16
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Well Done,
Did it actually feel quicker though?
Can I have the contact number to get these made up for me. I have been waiting for Celicamad to get back to me with it, but he has been busy.
Did you have the long twin pipe joiner or just the pik at the top of the thread.
Congrats again.
Pete
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Re: 1JZ Y pipe (again)
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Mon, 29 July 2002 03:05
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Its funny but the pipes if anything did not make the car feel that much quicker. However the results are there when you start running the times, and testing HP.
i think maybe the pipes smooth out the torque curve so much that there is no noticeable boosty region however there is more hp throughout the entire rev range resulting in faster times.
My exhaust system is outlined in a post above.
The best place to get them from is from newcastle exhaust services, details will be on celicamads website very soon, near windale. ask for Pete and tell them Matt sent you, be nice and he will look after you.
matt
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Location:
_Sydney _
Registered:
May 2002
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Re: 1JZ Y pipe (again)
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Mon, 29 July 2002 10:15
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Can anyone recomend some one in sydney that could do the exhaust system for me including the "Y" pipe for my soarer.
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