More than enough...

Vertical space is key. I've seen alot more twin setups on 3rd gens than 1st gens.

 

Only because most first gen guys are too cheap.

 

ive seen a few 3rd gen twin builds.. doesnt seam that bad.

the first gen is easy if you want a crappy 2 foot long hot pipe
i want mine to spool as fast as stock as i can.

lots of room beside the turbo on first gens just not below it.


look at my pics.
shortest 4" radius you can buy cut so there is like a perfect 90 and the turbo is a inch off the frame...took quite a while to get that right

if i tilted it to the outside id have more room but id would have to be too high for the inner fender to fit and well...........a crappy hot pipe.


i want to see the spooling difference between two first gens with s400 based turbo's

 

just a quick clip ..ill do another when its done

 

As someone who has been in a couple of twinned 1st gens with what you call a "crappy" hotpipe, I can tell you spool is more dependant on fueling, afc, and wastegate tuning.

 

Cold pipe looks good

 

ok crappy is the wrong word.

not ideal is better

i have seen newer twin setups. my first first gen.

tell me the characteristics of the spooling what levels of fueling they had etc..
i truly wonder how much of a difference it makes
maybe my extra efforts were a waste of time.

 

First truck, mine:
6x.016s, ported exhaust side of head, ported exhaust manifold, typical pump tweaks at the time, 366 spring, etc., etc. Wastegate set to be fully open by 25psi of overall boost. 57/65/14 over s475 with a 1.32 exhaust housing. Hot pipe made of 3 sch. 40 3" 90*s and a 3" to 4" sch. 40 reducer. Cold pipe is 3 4" 90*s.

Spooled about like stock until 20psi and then very quickly pegged the 60psi boost gauge. Peak boost was unknown because I didn't have a 100psi gauge yet. At the time I didn't have a tach, primary boost gauge, or drivepressure gauge installed yet. It's currently apart in the driveway for some more "improvements" so no more numbers for you right now.

Second truck, owned by Tacoclaw:
5x.014s, steedspeed manifold with external gate, not fully maxed pump, 366 spring, stock head. Internal gate set for 25psi, external gate dumping anything over 50psi to the downpipe to save headgasket for now until studs, etc. are installed. 62/65/12 over s475 with 1.32 exhaust housing. Hotpipe made of 3 sch. 40 3" 90*s and a 4" long or so section of sch. 40. Coldpipe is 1 4" 90*.

Spools about like stock, but just a good steady pull until the gated 50psi. He hasn't installed any other gauges yet either, so no word on the other stats. I have more fuel than Taco, and a looser AFC. His truck smokes less, but mine runs stonger and hits harder when the primary lights. He is running a very tight AFC to limit smoke. In my limited experience, having the AFC a little looser will let everything come on much stronger. I can notice a decline in spool with the AFC too tight. I'm not talking a freight train smoke, slobbering fuel setup. Just not as tight as everything will go. When I had a DennyT fuel pin, I turned it to the flat side once to see how much it would change things...boost went from over 60 to less than 30. The AFC can change alot.

With your wastegate... don't set it too tight or you will choke out your primary and make it (the primary) spool slower.

You have a very nice looking setup and list of parts. My point was tuning will be more important than hotpipe length (as long as we're not talking something crazy) when it comes to how well your twins work.

 

sorry been away for a bit.


thanks for the reply

why you limit the boost from the secondary at 25psi?
my he351 seams to like 30-35psi and its still in its operating range.
or are you setting it at total 25psi boost? little confused

and by "tighter" afc you mean starwheel/smoke screw up stiff spring.

i want to experiment with some different pins/afc setup....i dont want my truck to smoke like a train off the start as i pull a trailer often

right now my starwheel/smoke screw are way up to limit this but i actually found it spools slower and smokes less for longer then really bad for a short period.

kinda half a dozen of one 6 of the other kinda deal

what do you meen by " dont set up the wastegate too tight-it will choke the primary"
for example if i had it welded shut it would not choke it and if it is set to open too soon it will delay spool up

ill be installing the new BIG guage soon and was going to have my old 60 psi guage Tee'd off the wastegate hose on the he351 to help monitor in cab boost/tunning... was going to try and set it around 28psi start to open 36psi WO
hook the 100psi guage to the manifold..

i have no idea what total boost i will see............oh ya stock head gasket/no studs

 

The gate needs to open sooner to begin driving the primary, hence the "loose" setting. And adjust your wastegate with regulated shop air then adjust from there, much easier.

 

my gate already has some "bleed by" from the 1.125 drill bit catching and taking more meat then it should havewhen i ported it.


so if its too loose wont the top turbo run short of its "optimum" peak effiecency range? like 32 psi?

lets say it is wide open at 25, wont overall boost be lower and potential HP be available?


iam sure all of this will come to light when i start tunning and testing. and i will report back my results.

truck is in the body shop right now.

 

While I am for compound builds, you need to read more on compound tuning.

Sent from my rooted Velocity Ally

 

Here are a few helpful links for twin tuning.

http://www.competitiondiesel.com/for...t=tuning+twins

http://www.cumminsforum.com/forum/89...o-setup-3.html
^^^^
Read TURBOLVR's post on calculating secondary boost.

Also, here's a pic of the little regulator/gauge combo I use to setup my wastgate. Fits right in the hose from your wastegate, and only being a 30psi gauge makes it easy to see exactly when its opening.

 

thanks

ill be bringing it to the dyno after its out of the body shop and all together.
going to hopefully set-up a full day rate.think its a mustang dyno.

going to tune it with watermeth and if there is any $$$ left

if this thing doesnt put 500 down iam not going to be impressed

 

Interesting conversation on setting up the afc and setting up the internal wastegate. I run a pretty tight afc setup and I have my gate to dump at 38psi. When I decide which rout I want to go with a new set up I might just have to try some different things.

Probably going to go with twin ball bearing turbos and then set them up so I can run a bunch of nitrous if I want to. I was definitely not set up to run as much nitrous as I did, and that is why I blew my headgasket. Mine is studded and oringed which is why it probably lasted 9 runs on the dyno before it let loose.

Lucas1 with what you have I am sure you will be over 500hp with water/meth. Nice build.


Stomp