looking for twin advice

as a general rule a turbo will spool better as a single than if it's used in a twin setup... doesn't mean you can't have a better spooling twin setup using a smaller top turbo...

and you can have a bottom turbo that can help, but most setups don't offer that because most bottom turbos aren't gated. you put a nice tight turbine housing on the bottom, and that turbo will actually help spool, but you'd better have some pretty slick wastegates (top and bottom) to make it do what you want down low AND up top

most popular twin setups are STILL a compromise despite what people say/think
 
no, pulsation occurs in the manifold... once you reach the top turbo, pulsation is pretty much a non-issue. with a quality top gate that sees all 6cyls, you'll have some real pulses hitting the bottom turbo, but most commercial setups don't.
 
Forrest Nearing said:
no, pulsation occurs in the manifold... once you reach the top turbo, pulsation is pretty much a non-issue. with a quality top gate that sees all 6cyls, you'll have some real pulses hitting the bottom turbo, but most commercial setups don't.
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NO SHIZ it occurs in the manifold :bang man forrest its like you are all confused and have gone buck wild in your own koolaid. :hehe:
 
IMO if you're only at ~500RWHP you wont like the 40/3b. I dont care what you do you dont have the fuel to spool it fast enough. Been there done that. IMO you'd be better off keeping your turbo. If you have to have twins a 35/3b or 400 would work better.
 
TMONEYDIESEL said:
NO SHIZ it occurs in the manifold :bang man forrest its like you are all confused and have gone buck wild in your own koolaid. :hehe:
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ahh, I see you mentioned a cam earlier, sorry... but you didn't really expound on the fact that head work and a good cam will help spool turbos :eek:
 
Forrest Nearing said:
ahh, I see you mentioned a cam earlier, sorry... but you didn't really expound on the fact that head work and a good cam will help spool turbos :eek:
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Took you long enough :clap: Yea im sure your another one that believes huge intake porting on your head helps spool your turbos on a inductive motor. :charger:
 
TMONEYDIESEL said:
Took you long enough :clap: Yea im sure your another one that believes huge intake porting on your head helps spool your turbos on a inductive motor. :charger:
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well... intake side porting does help (more oxygen in = bigger bang in the cylinder = more exhaust energy at the turbine)

not sure what you mean by "huge" intake porting, but I certainly don't subscribe to the backwoods/redneck "hog it out" school of portwork

you got anything else to try to make me look stupid because I made fun of your favorite grill manufacturer? :confused:
 
Forrest Nearing said:
well... intake side porting does help (more oxygen in = bigger bang in the cylinder = more exhaust energy at the turbine)

not sure what you mean by "huge" intake porting, but I certainly don't subscribe to the backwoods/redneck "hog it out" school of portwork

you got anything else to try to make me look stupid because I made fun of your favorite grill manufacturer? :confused:
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Yea because when you have 60psi and up slamming its way into your cylinders and as soon as your valves open the psi is already there you dont have to worry about porting your intake when you have a INDUCTIVE motor, It would definately help you out on a aspirated motor, but the air is already there waiting to come in. Port your exhaust to help it get out but thats all you need, No Forrest i dont need anything else to make you stupid LOL and RBP is not my favorite grill manufacturer i prefer a Weber LOLLOL You know they do make more than just grills :what:
 
And meanwhile back at the farm............


I say go with the 40/3b. They are cheap to put together just make sure you match your housings to what you are gonna be doing. Dont have a 18cm on the 40 and a 32cm on the 3b unless you like waiting for ever to spool and smoking everytime you touch the throttle.

I have the 40-16cm/3b-23cm and it works good. The 26cm on the 3b is also good.
 
TMONEYDIESEL said:
Yea because when you have 60psi and up slamming its way into your cylinders and as soon as your valves open the psi is already there you dont have to worry about porting your intake when you have a INDUCTIVE motor, It would definately help you out on a aspirated motor, but the air is already there waiting to come in. Port your exhaust to help it get out but thats all you need, No Forrest i dont need anything else to make you stupid LOL and RBP is not my favorite grill manufacturer i prefer a Weber LOLLOL You know they do make more than just grills :what:
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here ya go big brain...

regulate your air compressor down to 60psi... put a 3/8" orifice at the end of the hose and record how long it takes to fill up a 5gal trash bag full of air.

now... put a 1/8" orifice at the end of the hose and record how long it takes to fill up the same trash bag.

by your... uh... logic? they should take the same amount of time because there's 60psi on the back side of your orifice, right? :umno:

you realize that on a naturally aspirated engine, there's 14.7psi of pressure at sea level slamming its way into your cylinders right?

there's a SLIGHT difference between density and CFM... you can move the same amount of oxygen at higher density with less CFM, but if you maintain the same density (boost), if you open up the port to flow more CFM, you WILL move more oxygen at that same density. :eek:wned:
 
dodge359 said:
And meanwhile back at the farm............


I say go with the 40/3b. They are cheap to put together just make sure you match your housings to what you are gonna be doing. Dont have a 18cm on the 40 and a 32cm on the 3b unless you like waiting for ever to spool and smoking everytime you touch the throttle.

I have the 40-16cm/3b-23cm and it works good. The 26cm on the 3b is also good.
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I'm running a 40/16 3B/32 set now and have NO lag issues. I suppose if you had only 350hp you'ld have to run smaller housings but as with ANY turbo you must choose wisely taking the whole picture into consideration.

As for porting... in ALL forms of racing porting is done to maximize flow for a given condition. All thing equal a properly ported engine will ALWAYS make more power than an unported one, often at a lower boost. boost can also be referred to as restriction. forrest did a nice easy job of explaining
the concept.*bdh*
 
I haven't had any luck with anything BD. But I sure do like the small twins I have of theirs. I can start to make boost at 1200 rpm. driveability is SO much better then with any of the singles I have had. But there is a hp limit. I only want 500 so this setup works well for me.
 
not to sound ignorant or hijack thread, but how exactly do twins spool slower than a single? I thought that one was of the appeals to having twins was that it could spool the big charger quicker.
 
Smokinrebel said:
not to sound ignorant or hijack thread, but how exactly do twins spool slower than a single? I thought that one was of the appeals to having twins was that it could spool the big charger quicker.
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a pair of twins will spool better than if you just ran the bottom turbo as a single, but vs. the top turbo, they're going to hit later and slower.

the big turbo acts as a restriction on both the intake side and exhaust side of the small turbo...

think of it as a restrictive air box and a restrictive muffler... that little turbo is going to spool slower w/ that restriction. difference is that bottom turbo will light up eventually and start feeding that top turbo efficiently pre-compressed air. so at a given boost level, you will actually have greater density due to the combined efficiency of the two compressors vs. a single compressor
 
but your thoughts are still correct. To make the bigger hp you need a bigger turbo.. Orrr you can get a small turbo and an even bigger turbo and lite faster then the one big turbo.. I can lite my twins a whole hell of a lot sooner then any single on my truck. Even quicker then my PDR35 I had on there years ago.
 
I haven't had my twins long, but more and more I'm finding that a lot of it comes down to tuning and getting your setup dialed in. At first I was experiencing a bit of lag. Not too bad, but my 35 was lighting a little slower than it had been before. By playing with the settings on my drag comp, and my external gate, it seems to be getting better all the time, with faster spool up and almost zero smoke.
Sean
 
sstockton said:
I haven't had my twins long, but more and more I'm finding that a lot of it comes down to tuning and getting your setup dialed in. At first I was experiencing a bit of lag. Not too bad, but my 35 was lighting a little slower than it had been before. By playing with the settings on my drag comp, and my external gate, it seems to be getting better all the time, with faster spool up and almost zero smoke.
Sean
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:snoop::clap: the best parts will still suck if not set-up properly.
 
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