Twins finally together! GOt some questions!!

O

oldsmokey97

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Aug 5, 2006
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Well, ive been kinda tinkering for about the past week with this and... I finally got my twins fabbed up and in the truck. Now i got some questions.

Combo is.. HTB2 64/14 and a 74mm S400.

Spool up takes forever but i think i may have too much fuel down low. If i just lay it to the floor..... she doesnt fully spool untill around 3400 rpms.


Now for some questions:
1. When does an external wastegate become mandatory?? or is it already?
2. boost is around 65 psi. THis seems low, is this normal??
3. pyro pegs out quicker than before at WOT.

WOuld a small shot of NOS help to spool these things up at the track??

ALso.............. what would be the best way to get more Boost out of this setup??

Lance
 
Tune your AFC- slide it all the way toward the driver's seat and move it forward in increments until it feels right. It sounds like way too much fuel too early. May want to try a 100 plate if that's not working?

Boost seems about right. You have a ported head, they always seem to drop the boost. However, build a pressure tester and check for leaks since you're seeing high EGT.

Set the 64mm internal 'gate to start opening at 20psi that should help spool the s400.
 
1. I have no idea.
2. How much boost do you want? Boost usually means heat. 65 is pretty good.
3. What is pegged to you? You might need to open your waste gate sooner.

NOS on mine cooled it down 200+ degrees but timing becomes a real issue with giggle gas.

How much smoke are you making when shes all lit up at WOT? You may be able to take some of the low boost fuel out with the star wheel.

Your set up is similar to mine (except the race head, mine is a stocker with springs) and I dyno'ed at 587/1264 on w/m which gave me 63hp.

Im just talking out my a$$ here so hopefully someone with more experiance will chime in.
 
What pressure do you have your top gate set to open at? You might want to try 30 to 34psi. That will be set at a cracking open point. Tune your afc so your fuel curve comes in later. Try to tune your air ahead of your fuel as best as possible. Hope this helps. Good luck!
 
oldsmokey97 said:
Well, ive been kinda tinkering for about the past week with this and... I finally got my twins fabbed up and in the truck. Now i got some questions.

Combo is.. HTB2 64/14 and a 74mm S400.

Spool up takes forever but i think i may have too much fuel down low. If i just lay it to the floor..... she doesnt fully spool untill around 3400 rpms.


Now for some questions:
1. When does an external wastegate become mandatory?? or is it already?
2. boost is around 65 psi. THis seems low, is this normal??
3. pyro pegs out quicker than before at WOT.

WOuld a small shot of NOS help to spool these things up at the track??

ALso.............. what would be the best way to get more Boost out of this setup??

Lance
Click to expand...

Take it to Bobbys shop he will tune them right up..... :hehe: Good luck...LOL
 
I think the slow spool might be due to the 64 on top. I'm sure that is slowing it down some. I have my wastegate set to about 25-28psi and they spool NOW! I see max boost of 65psi by 2600rpm. I wouldn't go over 65-70psi or it will be hot air.
 
well.... after doing some looking this evening..... I have found some exhaust leaks.

The plate on the side of the 64 that is covering where the internal wastegate is has a major leak. Exhaust is just shooting out from around all sides. What is this about??

My mind is blank right now.... so...... how do you go adjusting the wastegate on the 64mm lower than what it is set at from HTT?? I have always just used the adjustable elbow. DO you make the rod longer or shorter?? Also, how do i know what it is wastegating at when i have no way of knowing what it is doing??

Lance
 
Im not sure if they are like a Holset but on the holsets you take off the acuator and drill the little dimple in the connecting rod and then you can screw the connection rod in and out.
 
hook a pressure gauge to a blow gun and from the blow gun hook it to your waste gate only and SLOWLY turn up the presssure untill you see the lever move that will be where the gate starts to open and a little more and it should open up a lot kwicker use the blow gun to try it a few times you should set the top turbo low like around 25-30 psi to keep EGTs down I have mine set at 20psi but my top turbo is stock and lights fast so try that you should be able to get a regulator from napa or any auto motive store try and get a lower pressure one like 0-65 PSI and after getting all of that and still doesn't spool you can try a snail housing or put a hx35 on top it works great for me 580rwhp daily driver
Good luck!!!!!!!!!!
 
oldsmokey97 said:
well.... after doing some looking this evening..... I have found some exhaust leaks.

The plate on the side of the 64 that is covering where the internal wastegate is has a major leak. Exhaust is just shooting out from around all sides. What is this about??

My mind is blank right now.... so...... how do you go adjusting the wastegate on the 64mm lower than what it is set at from HTT?? I have always just used the adjustable elbow. DO you make the rod longer or shorter?? Also, how do i know what it is wastegating at when i have no way of knowing what it is doing??

Lance
Click to expand...
HTT's are setup so you can turn the wastegate arm. Making the rod longer (turning counter clockwise) will decrease boost. However, I would look for intake tract boost leaks. Fix your leaks before adjusting anything else. IMHO, the wastegate is the last thing to tweak.
 
well i lokked tonight and found some major major boost leaks. Boost is now up to about 75-80 psi.

I got one more boost leak to fix and then i will be good. I think i am going to need a bigger bottom charger after all.

I still have not lowered the wastegate on the 64mm because i did not have a snap ring pliers small enough at the time to take the rod off and lengthen it so i will do that tommorrow..

Lance
 
Turn the nut on the arm. It's a threaded rod that will shorten or lengthen the actuator.
 
I called high tech and they said to extend the rod about 10-12 turns. I did this and it seems to spool a little faster but it still does not HIT as hard as my 64mm did as a single.

How much is too much boost for the 74mm?? I ran it at the track last night and was seeing around 75 psi with spikes to 80.

Lance
 
A compound setup will spool slightly slower than it's secondary would if it was used as a single. However, you may be able to run a smaller exhaust housing on the secondary which is where the twins advantage comes into play.
 
i think i may be going to an 80mm for the bottom turbo.

Egt's are just way too high with the current setup.

I have a tial ext. wastegate on the way that will soon be going on so maybe that will help.

lance
 
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