question about single versus twin

[figgie]

Suprahero..

have you checked my turbo-calc sheet in the turbo subsection?

http://www.supramania.com/forums/showthread.php?t=80948

That sheet has all the garret turbos but it can get you close

 

[suprahero]

No, but I will. I'll check them out tonight. Thanks.

 

[SupraClaou]

Speedforsale.com has a twin-turbo set up for 2jzgte that is working in
sequential mode (factory/oem mode and looks):biglaugh:
Two GT28R turbos in the stock CT12/CT20 Toyota housings!!!!
This kit in the sequential mode can go up to 550 rwhp!
This should be amazing....while you'll get turbo wine before 2000 rpms and
no lag at all :love::biglaugh:

 

[figgie]

two GT28R and only 550rwhp? Hmm. Sounds like they are being choked to death (ie stupid high turbine speeds and not enough room to let them breath and probably to the left in the efficiency islands for both). 125k rpm turbine speed, choked to death.............I wonder how long that setup is going to last.

 

[OneJoeZee]

you think i would be able to make up for these lost numbers with 2 decent sized/ rated upgrades? i wouldnt mind a big single either though, i just liked the look of the tt but i didnt know it was a crappy setup... thanks for the support suprahero... btw my girlfriend just fell in love with that pic of ur interior like 2 minutes ago lol1

Twins are not worth it. Just go single. Get over the "omgz, two turbos!" thing. But that's just me. I tried it and it was fun while it lasted.

 

[OneJoeZee]

That said, if/when I have another 1J supra, I think I'll leave the stock twins in there.

I enjoyed the car alot more with the stock twins...

 

[SupraClaou]

two GT28R and only 550rwhp? Hmm. Sounds like they are being choked to death (ie stupid high turbine speeds and not enough room to let them breath and probably to the left in the efficiency islands for both). 125k rpm turbine speed, choked to death.............I wonder how long that setup is going to last.

Yeah...that's true.
And 550 rwhp on race gas + 26psi!
They do admit that there is restriction on air flow. They estimate that with
some more supporting mods like cams,ported or custom exh. manifold,ported
head,3"+(maybe 3.5") exhaust/DP,and quite big free flow IC + pipes ....could
give you some more whp. For sure more than 600rwhp and still having the
stock sequential mode!
I wonder if someone has this setup with those supporting mods! :biglaugh:

 

[jizake1jz]

two GT28R and only 550rwhp? Hmm. Sounds like they are being choked to death (ie stupid high turbine speeds and not enough room to let them breath and probably to the left in the efficiency islands for both). 125k rpm turbine speed, choked to death.............I wonder how long that setup is going to last.

550 hp? i thought thats pretty good for twin gt28r's. they aren't rated that high....

Twins are not worth it. Just go single. Get over the "omgz, two turbos!" thing. But that's just me. I tried it and it was fun while it lasted.

i want to get over the "omgz, huge turbo!" thing. i have an sc61 on the car now anyway. its not about the "wow look big twins," i want it to be "wow look at all the nice fab that went into making this setup. look how nice everything flows together and fits well into the given space. AND it make respectable numbers!"

but i also don't want to spend a ton of money on something that isn't going to work properly, which, from the above posts, doesn't seem like it will. anyone can buy the parts to bolt on a big turbo, but i want to be the guy that learned how to make all his own parts to try something a little different then most of the rest.

basically, will it work? will it be the worst choice i ever make? i honestly don't know, thats why i'm asking, but i want to put up a little argument so as to fully discuss the topic

AND if you had to go larger twins, which would you choose and why?

 

[viperkillertt]

5 Years after Toyota Introduced the Twin Turbo 1JZ ,they officially admitted that a plain Parallel twin turbo setup is WORSE than a Single turbo in the following article

Now for a more sophisticated Twin Turbo setups like the USDM 2JZ-GTE or even on some Audi(s) the story is quite different.

dude,
That article was awesome!!! I havent seen it before.Thank you very much!!!

 

[OneJoeZee]

i want to get over the "omgz, huge turbo!" thing. i have an sc61 on the car now anyway. its not about the "wow look big twins,"

It is for this guy.

because i like the whole idea of twin, the way it hisses, looks, and especially would love to brag about my twin turbocharged car.

 

[figgie]

550 hp? i thought thats pretty good for twin gt28r's. they aren't rated that high....

Considering that Garrett rated the GT2876R at 480 hp.... two of them should be able to do 700 easily. But we get into that efficiency thing again

 

[Gritz]

I wasn't suggesting that twins are better..i was just saying.. do your home work..then make a choice....And if the twin look is really what you want..go for it....Its more of a hassle with twins so keep that in mind...

 

[drewgo]

I am doing one as we speak. Should be fun..... I hope:x:

 

[jizake1jz]

Considering that Garrett rated the GT2876R at 480 hp.... two of them should be able to do 700 easily. But we get into that efficiency thing again

yes, buts thats a gt2876r, not a gt28r. as far as i know, a gt28r is just another name for a gt2560r, which is way smaller than a gt2876r.


you also keep saying efficiency. what do you mean by that? is it just a direct relationship with flow in this case? the stock 1jz came with twins. i don't understand how using bigger twins won't work well. sure it will be way different than a 42r(which as you said, i found to be a really nice match for the 1jz when i first started comparing a larger single to large twins), but a nice set of twins will flow better then the stock turbos, and i hope have power at a decent range. i never looked into it, but what is the powerband like on a 42r? i want something that can be used elsewhere besides a dyno and the dragstrip. thats why i thought a twin setup might make nice setup

 

[jizake1jz]

what turbos are those???

 

[figgie]

yes, buts thats a gt2876r, not a gt28r. as far as i know, a gt28r is just another name for a gt2560r, which is way smaller than a gt2876r.

No

Garrett does not play that mislabeling game.

gt28 is in thier 28 series turbo NOT 25..

gt25 series
http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT25/GT2554R_471171_3.htm
http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT25/GT2560R_466541_1.htm

gt28 series
http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2859R_707160_9.htm
http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2860R_707160_5.htm
http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2871R_472560_15.htm
http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2876R_705330_1.htm
http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2854R_471171_9.htm

not the same turbo. AT ALL!

 

[drewgo]

No

Garrett does not play that mislabeling game.

gt28 is in thier 28 series turbo NOT 25..



not the same turbo. AT ALL!

No Jizake is right.
The 28 series turbos are oversized 25 series. When they were crossing over the 2560r became the plain jane 28r.

http://www.turbobygarrett.com/turbobygarrett/tech_center/gt_basics.html

 

[88supraTT]

friggie thanks for response

here is a graph that i found digging for info. i understand the 1jz is at a huge disadvantage because of the displacement of the engine and which is why ive been going back in forth about what turbo or turbos to run ever since i decided to go with a 1jz in the fc.
note: I'm pretty sure this is a 2jz

 

[jizake1jz]

nice find on the graph! what do you make of it though?

EDIT: wait, is that twin gt28rs's? it looks like the only difference is spool time really, otherwise almost identical. this is very helpful

 

[88supraTT]

I'll see if i can find the thread, but it shows the gt40r is producing power sooner in the rpm band, is alot more aggressive coming on and is also creating more peak power.. versus the twins are a little more linear don't create as much, but also are not as agressive when fist starting. which is what i think will be better for auto cross. its hard for me to make decisions because i only know one other person with a 1jz in the area, and only know one other person..my brother running a large single. so all the information for me has to found on the internet.