cewrx7r1

iTrader: (2)

inlet pipe for the rear turbo for American cars?

The crappy squashed "S" curve is so that it can fit on JAP right hand drive cars since the brake boost cylinder gets in the way.

One with a single curve would allow the rear turbo to flow better. It is already at a disadvantage compared to the front turbo because of having a longer pipe to suck through.

jimlab

No offense Chuck, but that crappy squashed S curve doesn't seem to be holding anyone back...

If you can run high 10s and put down high 3xx RWHP with it, what's the point of going to the trouble to design a replacement for it? By the time that S curve becomes a restriction, you're likely out of the efficiency range of the stock twins, and should probably be considering a single turbo upgrade anyway.

duboisr

My mechanic looked into replacing that pipe when he installed the big BNR turbos. He did rework the turbo end to fit the flange he made for the intake housing . The cross section looked big enought to not starve the turbo . It is pulling hard at 17 lbs so it must be doing ok with turbos bigger than stock .

poss

iTrader: (5)

Yeah, Don't reinvent the wheel....right Jim?!?
Or is it "don't fix it if it ain't broke?"

SWAT81

iTrader: (14)

this doesn't have to do with the post but using that phrase may offend some people, its a term the US used to use against the Japanese people to look down on them.

EpitrochoidMan

Leave the politicly correct B.S. out of this please. This guy obvisously means no harm, and has a good question.

My heritage is a mix of many things, irish, native american, etc. I'm not offended everytime I see the Redskins play football or hear someone refer to a police van as a 'patty wagon' These things are only problems when people want to make one. What should he use, asian? (asia is a continent by the way, not a country) Are you an american? Or do you choose to make this kind of thing an issue-perhaps you prefer asian american, african american, or maybe european american (since we prefer continents over countries-irish american??)

All of our backgrounds are different and these different words we use to make distinctions are just that words, WHO CARES.

cewrx7r1

iTrader: (2)

With the attitudes shown by some on this post, we would still be living in caves if they had been our ancestors!

Yeah Jim, who needs a V8 either?

Tim Benton

iTrader: (1)

amen

Tim

Tim Benton

iTrader: (1)

amen to the political crap.

As far as the back pipe. it would still need to make 2 bends to fit onto the turbo inlet. would 2 90 degree bends roughly do it? I agree that it might not be worth it, but Chuck's just opening the floor for discussion and maybe we learn something from it

Tim

jimlab

OK Chuck, let us know what you figure out and whether all the work was worth the 5 horsepower you picked up. Hell, get your intake manifolds Extrude Honed while you're at it.

Yeah, who'd want a reliable car?!?

RX7SpiritR

iTrader: (1)

not me! I'll take the rotory thank you very much! You cant stop an enthusiast mister!

jimlab

A true enthusiast would probably spell "rotary" correctly...

clayne

I'd say it may be worth more than 5 HP.

What's wrong with trying to figure out a better flow design for the exhaust and intake?

jimlab

Maybe, but I doubt it. Replacing the pipe won't reduce the intake air temperature, won't increase the efficiency of the turbos, and won't decrease the pressure drop of the intercooler and piping. Therefore I fail to see how it could improve performance, especially since the boost levels at which the pipe might actually become a restriction are well out of the efficiency range of the stock turbos. Maybe a car with upgraded twins would benefit. Maybe not.

With a free-flowing cold air intake, the stock twins are already capable of pulling in enough air for 16-17 psi of boost, which is out of their efficiency range, and more than anyone would want to run for extended periods without race gas as a buffer. If there was a restriction in the intake path, it would be noticeable as a cap on the boost level, much like the MAF sensor on the MKIV Supra eventually becomes a restriction in the intake path, but only at boost levels you'd see with a single turbo.

Nothing. My opinion is that it's a waste of time in this case, but that's obviously not enough to stop anyone from trying it...

clayne

Personally I'd rather put the effort into single turbo applications - but I think anyone willing to design a
better mousetrap is fine by me.

Flow upgrades always help everything down the chain regardless.. Anything resulting in increased *CFM* is a PLUS.

jimlab

Not necessarily. For example, an aftermarket 52mm or 58mm throttle body on a stock LT1 is a waste of money because the stock throttle body is not a restriction yet. Once you stroke and bore the engine, port the heads, and upgrade the cam, then the stock throttle body may become a restriction. You have to be able to use the increased flow for it to be a plus.

duboisr

The pipe will flow well for bigger turbos so it is good for stock or upgreaded stockers .There is not alot of room for a larger pipe with out the flat section . The flat section is wider than the round section so the area is large enough to supply the air . The one my mechanic modified changed the lower end so the 90 degree bend was bigger and but a larger flange on it for the bigger turbo .

Mahjik

iTrader: (1)

Does he have any actual dyno graphs before and after to show that the modification actually did anything good?

I remember a discussion about this same topic about 2 years ago. However, I don't remember anyone actually doing anything to see if it made a difference. While I'm skeptical about the change adding anything extra, I'm also curious to see the results.

RonKMiller

What was it that Jack Webb (aka Seargent Friday) used to say in the old Dragnet series?

"Just the facts mam."

Jeez how I DESPISE these threads that always turns into a discussion by all the newbs speculating ad nauseum guessing how much extra horsepower a single mod makes -

Well, here's the answer for this one: exactly 1.27546.

Don't mind me, I have not had my breakfast and I'm a little low on blood sugar. Gee! *slamming forehead*: I could have had a V8!

(Sorry Jim, but nobody has really dissed you YET and I felt obligated to speak up for the ROTORY community)

cewrx7r1

iTrader: (2)

According to Jim, anyone who replaced their stock accordian inlet hoses with M2 or similar hardpipes were wasting their time and money. Then that also applies to replacing the stock elbo with a Greddy elbo.

And then of course the EFINI "Y" pipe is not worth it either.

Port matching gaskets etc is also a waste of time.

How about Paul Yaw, he even flattens out the butterfly shafts in carbs to decrease turbulence and get a little more CFM flow.

And we all know Jim's famous suspension bushings made such a differnce, rode and sound like a tank.

But what the **** do I know?

RonKMiller

LOL...all I know is the washers I put on my freakin' oil pan worked!

Tim Benton

iTrader: (1)

I'm a lazy *** who lets Jim work out new products If it were already made, then I'd buy one for the hell of it, like I did the CF driveshaft. But sitting down and justifiying the time and cost involved...and then testing to see if any performance gain was there...well I'd have to pass. Even if it added 3 to 5 hp at 14 psi....who would want to tackle the construction? I might jump out underneath the car today and take mine off and look at the bends.

Tim

turbogarrett

iTrader: (1)

i made a filter setup that basically bolts the k&n filter to the rear turbo, eliminating the s pipe. it was only to be used at the track. the car seemed to boost a little quicker(non seq) and really sounded cool at wot. i don't have any #'s because i popped my motor the next day, but the butt dyno felt like a few hp. i was about to order some mandrel bends and try to make something, but am going a different route w/ the motor

FormerPorscheGuy

I agree with Chuck. This would be something worth looking into.

I also think that ingenuity and clever ideas is the name of the game.

Let us know what you come up with Chuck, I am interested in the design.

jimlab

Now Chuck, there's no need to get nasty... or dramatic.

Which might be something Abel Ibarra would benefit from because he's exhausted everything else, but would the average FD owner notice any difference? Unlikely.

Well, it sure didn't take long for you to resort to personal attacks, did it...

Apparently less than I suspected...

I'm sorry that you think that my post was a personal attack on your idea. You posted looking for opinions, I assume, and I gave you mine. You don't have to agree with it, but you do have to expect that not everyone will agree with yours.

Someone serious about the idea would take a set of intake piping to a shop with a flow bench and find out exactly how much cfm it flows instead of just guessing. Next, calculate the maximum cfm required by the rear turbo to produce X amount of boost. If that figure exceeds or is close to the maximum flow of the piping, then there's room for improvement. If not, then this is all just idle speculation by a bunch of people who apparently have easily hurt feelings...