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MAXIMUM BOOST I CAN PUT?

1.9K views 25 replies 16 participants last post by  ElaineZ  
#1 ·
I currently have a a 77 Z converted to 83 turbo engine. I

Currently, I have A standalone ECU (electromotive)
The engine is from 83 ZX turbo (stock rod/piston). The only thing I've done is the metal head gasket, ARP bolts and head bolts, ported head, 36lbs injectors & intercooler.
Considering my air fuel mixture is right, what is the maximum boost I can put before the cast piston collapse?

tHANKS
 
#2 ·
How long....

I have run 21#, but the question is "for how long"?
I'm sure someone here has done more than that for a period.
I drove daily commuting to and from work between 12 and 17# for three years, and still have no Ill effects on a setup I installed in 87...
So at those levels I would say "longevity is not compromised in the least bit"....

I am in the shop today, BTW, running the "Green Machine". (Busa knows what that means!)
 
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#5 ·
ADROITCAPTOR

I don't understand why its getting worse?
Why would I go somewhere else like Hybrid Z?
Prettys sure there are tons of people has a Z turbo and they must know.
I searched "maximum boost" " how much boost" but I did not see any article....so

Tony had given me some info in the boost. He knows, it's his car.
Other's will say his boost is too high, some will agree
This help me assess mine. As a matter of fact, I want to beat 'em up
to see how much it can handle.



Post Edited (Apr 14, 9:10am)
 
#6 ·
Last month's car of the month put's 30psi on a turbo engine!

At high boost, >16psi you can't afford detonation so you need protection devices like knock sensors and solid electronic's to control timing.

A good IC is of course a must as well as monitoring and maintaining of air/fuel mixture.
 
#8 ·
Why would you go to another site? Because another site has a turbo specific forum. Because that forum gets more questions specific to yours. Because a moderator there has gone through and explaned thouroughly the most FAQs including the one you just asked. Or, simply to get another viewpoint.

Yes, it is all your fault that certain questions are getting asked more commonly. It is also your fault we do not have a FAQ sticky to help these people out.

Dude, lighten up! I was not giving you a hard time. Sorry if it came across that way. I was only saying that many people would be better helped, and would get answers much quicker, if we had a FAQ sticky. Nothing more
 
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#9 ·
"Dude, lighten up! I was not giving you a hard time"

You already did!

Yep its ALL my fault!
I MENTIONED I USED THE SEARCH AND COULD NOT FIND...SO
Yep! I have to pay for it, its my fault!
Yep! push me to other site...because you owned this and this is your
hangout site not mine.
Yep! I am invading your domain.....sorry!

SORRY FOR ALL THOSE FAULTS I MADE.
I guess... ITS A FULL MOON !



Post Edited (Apr 14, 12:02pm)
 
#10 ·
Get a grip. No need to go all "ElaineZ" on someone here.
Hybrid is a great site for getting info that is way outside the norm of production. Finding out how much boost before collapsing a piston should be able to be found on either site, but it's probably an FAQ at Hybrid.

Like Tony_D said, how much and how long is the question... Just a guess here but 1.5 atmospheres should be OK for a short time. Might more depend on the ignition and the condition of those old pistons.
 
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#12 ·
Hmmmmmmm, why so grutchy about it?
Help the guy.......
There are plenty enough Turbo Z tech guy here that you don't need to push someone to other site.
He said, he searched and didn't find any...so we help him.

Well, this what I noticed from some of the forums. Once a person hang out to a site, he thinks the rest is outsider (like a gang).
We are here to help. Yes, some annoying questions once in awhile but that's how it is! Otherwise why would you hang out here?



jon peter
280z & Lotus racing bike



Post Edited (Apr 14, 1:24pm)
 
#13 ·
These might be of help. Sometimes just changing your search to include less specific information does wonders. It takes a guess and check method most of the time.

just a few-
<http://www.zcar.com/forums/read.php?f=1&i=448442&t=448438>
<http://www.zcar.com/forums/read.php?f=1&i=448197&t=448197>
<http://www.zcar.com/forums/read.php?f=1&i=418646&t=418626> (N/A engine boost)

Again, please realize that I was not trying to be rude. I found the hybridZ FAQ to be very helpful which is why I suggested it. I do not know much and have no experience with these things. I can only point out the opinions of others and where I found them.

(I do not think you got I was joking when I was telling you it was your fault. I guess some do not get my jesting. But stop and think dude, how could you control others. Or control this site having stickies? I thought it was obvious you could not therfore the only conclution that could be drawn is that I was joking. no matter)



Post Edited (Apr 14, 3:24pm)
 
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#14 ·
Sounds like a simple question. If I knew the answer I would easily give it. I do agree that how much boost for how long is more appropriate. More HP has to take its toll eventually.
Im beginning to see why some hybridz people actually make fun of zcar.com, if you dont like the question skip it and browse the next. THis is like a soap opera some times.
 
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#15 ·
He he he!

Oh, MAN, that's priceless!
I think that should become a new part of "insider verbiage" here... "Don't go all 'Elaine Z' on me!"
LOL
 
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#17 ·
As one of the above post pointed out before this mess........ A stock T3 isn't going to work very well at high boost on a 2.8 liter. 15 or 16 should be max with an IC. Upgrade to a T4/T3 and 20+ psi is very possible on the stock cast pistons but high octane fuel (110+) is a must.
 
#18 ·
OK, the Shelby Dodge turbo cars and their owners (from whence I came) have T3 turbos stok that are comparable in sie to your ZXT T3's. They have routinely pushed them into the 30psi range. Nw of coure it won't have as lng a life, but if its a recent rebuild, it might shave a year or two off of a 10 year life span of the rebuilt turbo. So who cares.

TGhe thing about compressor eficiency is, if you can improve the airflow to the compresor, as well as the inlet charge before the compresor, then it helps, also the intercooling process makes a differenve depending on yor setup (NEVER go past 10psi without 'cooler!). A god intercooler and a good cold air intake should let these stocker T3's do 20 psi easy. Now, considering that the ZZXT engine has very low compression (7:1 I think it was right?) tit should be able to take that 20psi with no problems.

The real question is, do you have the fuel set up properly to support that? if not, you're going to turn your six-cyllinder into a big ass clusterbomb.
 
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#20 ·
Well, so much for the things that I created.
I am sorry that I cause all the commotions.

Back to my Z
Here is the story, my Z is original ZAP Z. I replaced the engine 1984 using the ZX 83 turbo. At that time, I was one of the few Z owner transplanted
a turbo engine. I gotten a wrong information from Bob Sharp mechanic
(I am a regular in Lime Rock CT.) He told me that the piston of the 83
is forged and the 81-82 are casted. I lost interest when someone told me that the 83 is not forged. I could have beef up the internals if I knew
the situation. I am one of those guys when I do a project, I don't want to do it twice.
This is the reason I asked how much boost that cast Z piston can take.
I am hoping that someone will come forward and say, I busted my piston
at this boost. Of course, there are so many factors the piston will colapsed.
Heat is the main cause and heat means so many things like AFM, timing,
cooling system, intercooling and such.
I have an RB26dett that I plan to install. I must have driven my Z 4 to 5 times since I replaced with turbo. The Z has been hibernating in my building and collecting tons of dust. I want to drive it hard and see what happen. I want to see if it can compete with the rice rocket in the main street.
I like to boost a lot. I have a lotus Esprit V8 and boost to 23psi all day long.
My love is the Z. I owned a Z since 1969 (240z) also Datsun 2000 and couple of 510's that I bought from Bob Sharp racing.

So, sorry for my question...I am just trying to get back to the main stream.
Been a long time I have not race either....perhaps its mid life crisis.


77 280z turbo
66 Lotus Super 7 Megabusa
2001 Lotus Esprit V8
1984 Lotus Esprit 910 turbo
Lotus Formula Jr.



Post Edited (Apr 14, 5:12pm)
 
#21 ·
ssssshhh!

intelligent, reasoned, informative discourse and converstation have no place in this post---please perpetuate the myths so I can still get stock T3's cheap!
LOL
 
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#22 ·
all depends on speed...

the efficiency map of the compressor makes a difference, true, but speed of the wheel determines the volume of air it moves until tip speed goes supersonic, and then all aerodynamic **** breaks loose.
The Hybrids capitalize on the fact the smaller turbine wheel will have enough energy imparted to it to spin a larger T4 compressor wheel in an overspeeded condition, making more air than possible in T4 / T4 configuration. Follow that?
Until the tip speed ofthe compressor reaches the surge point, it will make more and more air, usually on a parabolic curve. As long as the flow and pressure are "under the compressor curve" it will make air with little problem. May get hot, but it will make air....

I know a stock T3 will make 21#, I did it, but how will remain a secret. All I will say was I lived in Japan for five years, and there are things there.....STOCK things, that weren't available here, but work on all Nissan Products. Nothing like doing the "impossible" using all Nissan Stock Parts!

I mean, based on my experiences, 17# will run with no problems, and that was on an 8.5:1 N42 longblock! On a "real" turbo motor, I would go Hybrid and be living in the low 20's! Matter of fact, that's what I will be running in my 73 ZXT when this 260ZXT project is done for the wife (15psi, limited to around 300hp to the wheels). It is, after all, for the wife to drive daily...



Post Edited (Apr 14, 5:58pm)
 
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#23 ·
It's no secret, it's like I said, if you work with the air charge temps both before turbo (CAI) and after turbo (intercooler) then you an push T3's into 20 and well beyond. Sure a T3 is not going to flow like a T4 compressor, but its not just about the volumetric efficiency of a turbo, its also about air density going in, and going into the TB.
 
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#24 ·
Shane (not shane280z) ran 23psi at the strip for MANY seasons on a single junkyard L28ET. But you'd be taking your chances with a stock T3 - he ran a big hybrid (T3/T4) and consistantly ran in the low 12's on street tires, high 11's on slicks.
 
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#25 ·
I said SHHHHHHH!

My supply of "junk" T3's is going to dry up if you guys all keep telling the TRUTH!
LOL
 
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#26 ·
Oh, MAN, that's priceless!
I think that should become a new part of "insider verbiage" here... "Don't go all 'Elaine Z' on me!" TonyD


I second that motion!! People DO need to voice what they think... And Im quite elated to think, that I ...as a woman... Will be remembered for not putting up with ANYONE's bullshit!! And for standing on my own!! But I must admit Im sorry I didnt think it up myself!! Thank you for such respect!!


ELAINEZ ..... :eek:)
 
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