FastCat17

I have always wondered. Why do most people go single after their stock twins go out? What is so great about single compared to as if you were to get new twins upgraded or like 99 spec or even big *** twins like T28's. and what are the pros and cons about single and twin?

Nuvolari

iTrader: (4)

stock twins suck.... bad design , they build up a ton of heat . And to find a "non-cracked mainfoild " is getting impossible with rebuilt stockers .The 99 spec are good turbos , but if your going to spend 3k for a new set that at best can deliver 300 -440 rwhp, when a single set up can give you a ton of flexibility, depending what set up you want .300 rwhp-500+. It seems a bunch of "road race " guys are going with the Apexi 6 , or the Garrett gt35/40. Spool up is as fast as the stock twins and tons less headaches , vacume lines ect....

jdhuegel1

Yup. It's all about simplicity. No more hunting for the problem if one occurs.. There's so little to look at it's tuff to miss something out of place.

I can't really agree with the heat thing as my TO4R sure can cook some ****.. But It's a turbo. Turbo = heat no matter tha application.

Railgun

Here's the short of it.

Twins are more fun to drive on the street since they spool so fast. It's cheaper. And that's about all.

By going single, you axe the bazillion hoses and wires associated with making the twins (in sequential operation anyway) function. You get a much more linear powerband, as well as predictability. Your power potential is greatly increased, you'll unclutter the engine bay and it will look cool as hell.

I had originally planned to upgrade the twins this winter, but after having some minor issues, and some convincing I said to hell with it and went all out (see sig).


Spool with the single will be just off the mark as compared to the twins. They are tiny. Even though a 35/40 is BB, it's still bigger. I've seen anywhere from 200-600 RPM higher to hit say, 15psi. Unfortunately I didn't mark what my twins were doing, but I'll be sure to keep an eye on what it does now.

It's ultimately what you want to do. I want to do some road courses. I've only gone twice so far, both times with the twins. I'll have to let you know how the difference is the next time I go out.

DamonB

Everyone always speaks so highly of the single being cost competitve but they're wrong IMO. If a car is stockish going single is a big expense. After you buy the turbo kit you still need intercooler, ecu, fuel system & injectors, fuel pump interooler pipes, etc. Faced with bad stock turbos switching to '99 spec turbos is far cheaper than going single unless the car is already heavily modded.

NewbernD

iTrader: (1)

I disagree. Apples & oranges.

I think that if anyone running a single was shooting for similar HP numbers as the twins (small T04e at 10 lbs?) then you could feel comfortable with the stock fuel system and IC. I'd bet that on a stock port engine if you kept the boost to 10 lbs you could run the factory ECU also.

Small turbo ($400) + manifold of the week ($300) + downpipe ($200) + oil plumbing ($100) would be way under a set of '99s, spool respectably and run out of steam in probably about the same time too..

particleeffect

you have to understand also, that there are thousands of single turbo options available. there is only a handfull for using the stock sequential turbo's (99spec, or some other version of just replacing seals and wheels). you just don't have that many options using the stock housings and mani.

you can even match the spool of the stockers with a nicely setup single, so why bother with all the fuss the stockers have.

heat retaining, restrictive maniforld.
overcomplicated seq controll system.
the extra retained heat and extra mass of dealing with 2 turbo's.
being basically stuck with the stock housings.
extra piping of 2 turbos' air passages and oil lines...

i don't know how advanced ball bearing turbo tech was in turn of the 90's, but it's probably come a ways and the cost has come down some. not to mention how cheap you can get jurnal bearing turbo's.

i don't understand how it can be said that a single setup costs substantially more than using the stockers, other than replacing good (if this is the case) turbo's. you can't really run more than 10 psi without an ECU. and the hp you target will cost you the same fuel mods with either turbo setup. same goes for the IC, it basically needs to go regardless.

modrx7

iTrader: (1)

R U SERIOUS?

jdhuegel1

Who?

XSTransAm

who said the stock twins can push 440whp?

i would like to see the dyno graph

Nuvolari

iTrader: (4)

ok 440 is a bit high, but the last time I wrote you cant get more then 400 out of stockers I got slammed on the 3rd gen forum.

The best I could squeeze out of my BNR stage II's was 350 . Personaly I think anyhting over 370 is as impressize as a big foot , or Elvis sighting .Even if you can at 15psi them little twins wont last long

modrx7

iTrader: (1)

FastCat17

DamonB

The question is money. You guys telling me that it's cheaper to go single than to just buy '99 specs and bolt them on? Bologna.

NewbernD I would love to see examples of a $1000 single turbo conversion...

particleeffect

the way i see it damon, is that with the 99 specs running more air, you will need ECU and IC, and fuel modds past ~350hp. if you just slap them in and run 10 psi you aren't "upgrading" anything. you might get a handfull more hp over the stockers @ 10 psi but your still losing hp in the stock IC and runing only what the stock ECU will let you.

sure you can rebuild the stockers and run them on a totally stock engine setup, but that isn't an "upgrade" of anything.

the only cost difference really is between rebuilds/99 specs of the stockers, VS the cost of a single turbo and it's manifold/dp. which can get done easily as cheap as new 99 specs.

to use either efficiantly, you have to replace the same ammount of supporting items.

XSTransAm

AND
wastegate, intercooler, all necessary lines and boost controller... but hey thats only another 2 grand

DamonB

If it only cost $1000 to go single everyone would be doing it...

Lets assume you do absolutely nothing but bolt a single on the car; no fuel, ecu, intercooler or tuning mods whatsoever. You'll need at minimum:

turbo
wastegate
manifold
intercooler pipe
down pipe
some method of boost control
oil supply and drain lines
cone filter

Where can I buy that for $1000?

jdhuegel1

You can't.

I think this argument is a little silly. There really is no simple budgeting these cars. Cut corners one place, break somewhere else. You can make a rock hard performer in each arena, however for them to compete equally will require similar number of dollars..

NewbernD

iTrader: (1)

So would I.. I doubt we ever will though because no one makes a 'performance kit' to keep the same level of horsepower. Anyone capable of building one is most likely not going to settle with stock power levels either. I've seen pics of a few smaller turbos that ran on the stock fuel system and IC.. I don't recall what sort of EMS they had.

I suppose my comments were aimed at the way you used "going single" to automatically imply "boosting HP."

I don't know anyone who thinks that 400+ RWHP is cheap. I don't know anyone who thinks that you don't need to upgrade a lot of stuff to support it either. You're not breaking into that area with '99's by just bolting them on.

DamonB

I never made any comments at all on horsepower. The question as it is posed reads as "Why do most people go single after their stock twins go out?" implying that going single is a replacement for dead twins. It is not. It's an entirely different ballgame.

NewbernD

iTrader: (1)

No they wouldn't. Everyone's eyes are bigger than their brains. The audience for a single turbo setup that isn't much larger than a TII turbo would be non-existant.

I don't think the $1000 figure would be so off if you don't set your sights too high and have someone who can help fabricate (I take that for granted with what I can do for cheap verses what others can do..) In that HP range there are many turbos available with an integrated wastegate. You should be able to pluck a small t04e/57 off of eBay with an internal wastegate for $400. IC pipe doesn't HAVE to be polished aluminum. Scraps and bends... mild steel.. $20 for an eBay intake filter.

Cripes, man.. I'm not trying to sell you on the idea, just that it could be done. Small power parts are cheap. Building a "kit" out of them would be silly.

NewbernD

iTrader: (1)

And to totally beat this into the ground..

If you're not bumping HP then you don't need an intercooler, ecu, fuel system, injectors, pump, etc... any more than you would with the '99s.

That was my only real point.

fastcarfreak

Basically, people upgrade to a single turbo when there twins go, because people like to make there car go faster and this gives them a reason to do this. Most people wont justify spending an insane amount of money to make their car go faster. With the twins going out, people think, "well since its gonna cost this amount of money to do this, might as well just spend this and do it right". Thats basically what i did.

particleeffect

nvm.

sk8world

iTrader: (5)

That's the boat I am on. Can not seem to figure out my transition problem on my stock set up so I am considering to go with a mild single set up. The stock turbo's have been fun but this has gone on too long and what a head ach...........

spyfish007

The point Damon is making is for a stock car. He is saying that there are still some opportunites for twins to be applicable. You could easily bolt up some '99s on a stock car, no intake, ECU, or exhaust. You can't really bolt up a turbo kit without those mods, even though I've seen some people try. Twin turbos are popular in CA where emissions are so strict. Damon doesn't seem to be talking about making 300++ HP ... he is talking about much less-stock!

For people who have HP goals, then everyone else's arguments come into play. Single turbos get the heat away from engine block so the coolant o-rings will last longer. It is simpler because there is no more solenoid rack. There is no possibility of a transistion spike. The car is generally easier to work on. Last, but not least, you can usually have the turbo rebuilt which will save money in the LONG run.