Competition Home Made Twins- Performance

[Partyat33]

I don't have a lot of data yet, but after a weekend at the DHRA finals in Byron Illinois, here is what I learned.



I adjusted the external wastegate to limit boost to about 60 psi. It seems to work very well. With the powermax at 3 or less I would hit 1600 degrees on the track (single turbo). I ran this weekend with it on 7, and hit 1309 max. That was exactly the improvement I was looking for. I also shaved about 1/2 second off my time.



Under about 15psi the pipe between the two turbos is in vacuum. About 15 psi the big turbo starts to come on. I have not measured drive pressure yet and I could not see how much boost the big turbo is making when I am at 60 PSI total. At about 30 PSI the big turbo is making about 8 PSI. Lag is no more than with the single.



Right now I am pretty happy.



Little Turbo-- PDR HX35-12

Big Turbo--BHT3B-22

Wastegate is 40 mm.



Dennis

 

[TxDieselKid]

Dennis,



Sounds like your having fun tuning your twins. What type of injectors do you run? What were your times this weekend?

 

[Partyat33]

I ran a 16. 8 down from 17. 3. The injectors are a 4 flow injector from ADT.

I could run a better time with better shifting (6 speed) and I am too chicken to launch it hard off the line.



But I am having fun, the o-ringed head seems to be holding. !!!!

 

[BigDan]

Dude your truck can handle a hard launch.

I ran 16. 4 with a 2002, QC, 4X4, LB, HO6speed, 34" AT's

stock with an EZ.



I bet you can get into the 14's if ya tried, Definetly 15's



With the 6 speed its more driver then truck at the track. My first time there I was pullin 17. 1's with stock tires, after some more practice I was running 16. 4's and that was with bigger tires which I could tell stole some power.



Hang in there and good luck

 

[Forrest Nearing]

what were your trap speeds?

 

[BigDan]

HAHA Lame if I can remember 79-80mph

 

[HoleshotHolset]

Dennis! You finally got to really try 'em out! Oo.



I'm glad you got it all together and working well. I told you it could be done.



Matt

 

[Partyat33]

Yeah, they are pretty sweet. I am going through the trap at 82 mph at redline in 5th. I probably could pick up some time if I shifted earlier into 6th. Too bad you just can't practice all day.



Matt, JR Adkins said the welding looked very good. Good thing I did not do it !!!

 

[Mark_Kendrick]

Dennis,

You should be running those speeds in the 1/8th.



I ran 9. 2 1/8th @79 mph running a silimar setup on my dually.



Got any pics of your twins?



Later,

Mark

 

[Partyat33]

Guess I need a lot of practice. Or is it something about having to make sure I can drive it home with a 9k camper it tow. Either way, I am having fun. Question for you guys with twins, do yours behave the same way ? Until about 15 psi total the big turbo is being pulled along ?

 

[Mark_Kendrick]

It takes a few thousand miles for the big turbo to break in fully. You will see an increase in spoolup speed and lower EGTs. Until the at least 10psi there will not be enough exhaust flow to spin up the 3B. It's usually a little higher but you said you have a 22cm 3b. . it'll spool a little earlier.



What RPM are you shifting at? have you put a switch on the white/orange wire?



Mark

 

[HoleshotHolset]

Matt, JR Adkins said the welding looked very good. Good thing I did not do it !!!

That begs a question, Dennis... how much did you save by going this route? Did the PITA factor justify some of the cost of buying a complete kit?



I'm bound to have a spool pig of a truck with my HT3B/36cm²... nothing some RPM's and lotsa fuel won't help.



Matt

 

[Mark_Kendrick]

Matt,

You'd be suprised at the results. Yours will probably be a litle lazier but make good HP. it will run near to stock until you stomp on it.



You won't save much money building your own unless you have a well equipped shop and you count your time as free.



When you buy your parts you won't get the volume and dealer discounts on components. You will also waste a few parts while fitting your first set.



If you're building some give me a call and I'll give you a few measurements that will help you out.



Thanks,

Mark

 

[Partyat33]

Well, I had to pay a fab guy to weld it all up. Including the 5" exhaust, all the parts and the labor I got about $2500. 00 into them (that includes having the welder install it all as well). I probably spent too much on too big a wastegate, and I paid an extra $75. 00 or so cause I wanted a 22 or 23 cm housing and not a 26 or larger. I really don't know if it makes a difference or not. So far so good.



Dennis

 

[Mark_Kendrick]

You did pretty good. The giong rate for a twin kit is ~$3k.



My first set cost me around that. I have the ability to make them myself, from memory now. the biggest difference is not having to pay retail for the parts when you run a shop. But owning all the tooling is expensive.



I now have a Miller Synchrowave 250 TIG and a Millermatic 251(with the optional aluminum spool gun of course ). They're real handy for all kinds of things when the twins aren't sellin.



I'd like to see some pics of your setup. are there any posted?



Later,

Mark

 

[HoleshotHolset]

Good deal, Dennis. You made out just fine.



Thanks for the comments, Mark.



Matt