obZidian

iTrader: (2)

Ok, so here is where im at....

I want about 1100rwhp or more through a 408ci, 4l80e, stock style suspension vert.

there are a few differents i can go. This isn't my first turbo project, but given the fact that i have never had a 8 cylinder turbo setup, i want to ask the select few that have done it and know from experience.

Im not looking for a "which setup will get me the power" or "What i need to make this power"

My inquire is HOW will these two different, generalized, setups FEEL on the street. A few factors:

Boost response, power productivity, STREETABILITY, mechanical easy. Its got be smooth and powerful, run a a2a and possibly retain the a/c. (I completely understand that a/c and turbo kits is almost taboo, but this is a hurddle i have set for myself, if not at least to maintain my attitude while driving this car around in miami) It has to have the sense of a low boost, powerful street application with enough headroom to keep s all busy.

So, here ya go. PLEASE, add as much negative and positive feedback, if so, add what may be done to facilitate my needs.

1) 408ci big single turbo application. 91/94mm or a 101mm precision turbos. Adequate fuel, etc. appropriate a/r and housing. tang'd, maybe a .91a/r?

2) 408ci twin 72/76mm precision turbos. O course adequate fuel and matched a/r. (Im thinking something in the .68 range)


Ok, now with this, how will these two setups behave while driving around on the city? How fast will the boost come on? Will i have to wait to 5500rpm to feel any kind of power? How versitle (spellchek) can these two setups be?

I haven't made a desicion on which of the two i would go. I want this car to still remain streetable at an adequate, pump gas boost level, but if i want to unearth it, on the street, it has to be there and go.... not wait, wait, wait, them BOOOM!! its got to be as smooth as possible.

Sooo, let me have it!! Re think it you will, i just want to hear from how these tow setups might behave on the real world with dr's, real temps, humidity, taxis, traffic school, dual steering wheel mobiles, nd the occasional murcielago i run into that needs a quick rude awakening.

alright, hit it!! Im not doing this thread as a pointless inquiry from a person that wont get this done. IT will get done, just a matter of how then when.

laterZ!

Boostaholic

iTrader: (4)

Well with my twin turbo car, for streetability, you would never know it was turbo if you didn't get on the throttle. Street driving doesn't change unless you want to get into boost.

Power range I'm going for is 1200RW, and the twins you listed are capiable of that goal.

Mechanically my car is easier to work on than a stock car unless you have to mess with the motor plates, then it gets harder.

Boost response is very fast with my .96AR T70s, for your setup I would probably recomend a pair of Precision T67s, they will make 700 each and spool great.

hellbents10

iTrader: (10)

I usually go packaging constrants and expectations and goals. Sometimes twins can fill a gap at certain power levels where you cannot get a single in the size you want and vise versa. To a extent a single is considered to be a little more effcient all else being equall, but I would rather select between a single and twins with goals and packaging.

S-10's with small block for example, making over 1000hp. You cannot easily put a big single in it and rout a downpipe down one side. Twins are quite a bit easier.

LASTLS1

iTrader: (7)

Problems, 1100 rwhp on the street, why??? I run on slicks and turned down to 840 rwhp it doesn't work! 1100 rwhp for the street, your going to need a magic head gasket for that. Copper head gaskets leak water when used for the street. Think about what you really want and need. Good luck.

RyanJ

Since STEETABLILTY is in all caps, use twins closer to 60mm. I won't even get in to your HP goals.

As far as the "kit" factor in your post. DO NOT buy a pre-fab kit (excluding maybe one from Jim at Speed Inc...installed by Speed Inc.). Get a system custom made on the car. BTW, I'd actually consider stock fans and a decent coolant temp a greater factor for true street car than the retention of air conditioning. Either way, no matter what, you are absolutely giving up something to have a turbo car...whether it be space, ease, A/C, reliable cooling, etc. At the very least you'll be comprimising on turbo size to keep the A/C system in a stock location.

That's enough for/from me....

obZidian

iTrader: (2)

solution, 1100rwhp isn't for street applications, a low boost setting, somewhere in the 700rwhp will be for street driving. That is more then enough power to lay waste to just about anything i can come up agains't. If not, raise boost two pounds or so, remain on my pump gas without detonation, and then try it again.

My goals are set, however, i just wanted to see where everyone stood on the idea of a big single vs a twins setup.

Thanks for the gasket info, i'll keep that in mind. I haven't given it much thought so i guess now is a good a-time as ever, right?

thanks!

nitrorocket

iTrader: (12)

I am pushing 800 rwhp on the street with twin 61 mm PT61's. The car has way more power then can be handled. The bigger your HP goal, the slower the turbos will spool. Mine start spooling at about 3000 rpm and it ramps up to full boost (18.5) psi by about 5000 rpm. The car drives just like stock untill you mash the pedal, then the tires spin. I run 800 rwhp on 93 octane with a 347.

I would not go bigger then 67's, My 61's will make about 1000 rwhp and spool fast too.

obZidian

iTrader: (2)

Ok, if i went with a realistic bidget, a big single would be the my logical solution for big power.

First, anyone can give me a bit more info on the s88 than its 1500hp capabilty? Outlet/inlet diameters, flanges(i beleive its a t6) overall size of turbine and compressor housings, etc.

With my 408ci, a t88 would be a logical start. Packaging is a size retraint and if i went with a turbo in the battery location, i believe i can fit a t88, or even larger like a 91mm or even a 94mm precision turbo. It has a 4" outlet on the charged side so i need adequate intercooling piping to accomidate. I would regularly use 4" charged pipes to the intercooler, correct?

If i went with these a 91mm for example, and a tang'd .92 a/r, how soon/would i see peak power and how would it ramp (rpm specific vs throttle %) to my set shiftpoint of 6500rpm?

This turbo will give me enough headroom for good, solid big power yet be able to produce a tame 700rwhp level or higher on pump gas for street use. My only question is how would it behave while cruising around and i want to give it a good bit of gas.

For comparison, i would like to establish that we ALL know that tires and grip is limited. I know i mentioned streetability but this is all within the realm that we are all gear/speedheads and understand that even under a h/c package, tires suck!!!

sr71

iTrader: (17)

it all comes down to packaging. use which ever set-up is the easiest to build and fit. there should be no real difference in power or boost threshold between a big single and twins if sized properly. a big single will need a BIG downpipe. where as twins will need twice as much plumbing. pick your own destiny.

also, don't let people talk you into under turboing your engine. choose a turbo that will meet all of your goals while working in it's highest effiency islands on the map. the max rated hp of a turbo is usually at around 30psi. but, max effiency is usually at 50-70% of max flow. don't trade effiency for quick spool up. you will be sorry in the end.

I am building a 402 with twin 76mps's from forced inductions. will they be a little laggy??? yes. will they make huge hp???...YES!!!

RyanJ

ALL of the stuff you want to know is in this forum already. There are multipe twin vs. single threads, and a few threads about 91+mm turbos in which Jose laid out spooling estimates if I remember correctly. S88 info is in at least 2 threads, one being a very recent thread about Kyle's car being completed ("ATTN: Kyle Farley") and its got pictures of an S88. There's also threads on 40x buildups, fuel, different kits, consumption, etc. Just FYI.

NA$TY-TA

iTrader: (21)

Thanks You Ryan first off......

I have the S88 on my 370 and my low boost setting for pump gas (93) is 12-13 psi. and its a monster to control once it hits boost.


I cruise around on the new M/T ET Street Radials and its a lil scary sometimes.
Ive never hit the rollers and really have no need.
My high boost (20psi) the car is a whole new animal...
the math for a 3500lb car is about 900rwhp.....
Now my S88 sits were my battery once did. Just keep in mind everything else that is needed when you move things around.
My core support is moved forward and there is no way in hell we could keep my A/C. Now for cooling...... my Griffin Rad. and SPAL 16" fan work awsome and the car keeps nice and cool... even with a stock thermostat.. and thats been that way even in the last 100+ degree days here.....

i drive the car to and from work everyday......
OD would be nice with my 3.73's i have now but its so mean...... the lag??? i really never paid attention to it..... once i mash it the cars takes off like a raped APE (rAPEd) inside Joke


What are your other goals??? do you have a specific goal fo rthe car?? Track??? saftey Gear needed for a car that fast??

Now here's a BIG one...... How much $$$ do you have to play with??? set a $$ goal and start pricing out things..... u can go like this real fast.
Oh here is the S88 and yes its a T6 flange, 5" DP opening.



Kyle

Slowhawk

iTrader: (12)

Here is a graph of a 408ci,T88 setup to give you an idea on the power setup.This is at 8lbs,12lbs and 15lbs on straight 93 octain.I'm sure 20lbs would put you up near your goal on good fuel. Car drives 100% like stock

obZidian

iTrader: (2)

thanks ya'll...

ryan, i appreciate your comments but i have search a few threads and haven't found much on the s88 for the exception of the kyle thread and 408+s88 muahahaha thread...

Of course i will not let up on the search, that is half the fun,right?

Kyle, would yo happen to have more pics of the piping and the way its routed? More importantly, i want to know how much piping i can fit through the driverside, if i remove the alternator, through there if i routed the hot pipes from teh driverside back and arund through the passengerside. How much of a restriction will it be, in your opinion, ifi stepped that 5' opening down to a 4"? Or a 3.5" (WOW, crazy BP!!) EDIT: just found your pics page, nic build up!

Slowhawk, thanks!! I think i have seen that dyno before? Also, would you happen to know the a/r of that turbo off the top of your head?

obZidian

iTrader: (2)

Ok, got some picks of the ptk kit ( i know its a touchy subject and i dont want to promote their product, i just wanted to use it for subject reference. If so, please contact me and i'll remove the post, OR, if you wish, go ahead and delete this post, i would like to keep this thread working though... )

They run a three inch DP through the driverside. If i ran a crossover from the driverside to the passengerside, mated it to a merge and welded it to a t6 flange for my turbo, will i have enough room, through the driveside with a 4" DP? Also, let say i designed my hot pipes like these and ran a foward feed from the driverside, you think i can snake a 4" DP, REALISTICALLY, through there? I had asked this in the above post but here are some pics for illustration purposes. (only!)




If i use those clamps as a est. quide for the actually size of the 4" DP, i think it can be snaked through. However, there is a swaybar and a steering arm that may cause issues....

obZidian

iTrader: (2)

also, can anyone shed some lit on how close does the PS and steering rack gets to the DP and merge pipe in this kit?

obZidian

iTrader: (2)

Well, after some thought, the turbo project will be a single turbo, t6 flange setup with a few tricks!!

I had asked if ya'll thought it i could fit a 4" downpipe the way pts routes their downpipe?

Here is another one, most have routed their DP through the space where the ac compressor used ot be. What about the driveside.... i dont have my car wiht me so i cannot got outside and check any try to go driveside? THis is with a set of tubular headers, not truck manifolds.....

I noticed in a few pics that there is a fluid block for the steering, can these moved about to get more room through the driverside?

Well, here we go, Its crazy how the little things just build up and make a build like this go from 5k to 10k in one single phone call!!!!

Camaro_Zach

iTrader: (19)

you got that right, boy do you ever have that right hahahaha. what a hobby we all have...i swear...

obZidian

iTrader: (2)

hey, zach, you do websites, right? You did the site for nick and eric? Or am i thinking of another vette guy?

Pro Stock John

iTrader: (34)

Is this going in a C5?

My GT47-88 turbo is a T6 flange, and is physically huge. It's rated for 1200hp at the flywheel.

I'd probably focus on a 91mm turbo for 1100rwhp. You might want to research the GT 55-91.

DrTurbo

iTrader: (3)

A GT47-88 is rated well over 1200 flywheel. I would stick with a 91 thumper or GT55.