SPS 62 in twins. Drive pressure reduction?

[csutton7]

Ron--do you have an aftermarket cam in that engine??---chris

 

[RonA]

I have the mild cam that Piers sells with a 12 valve grind.

 

[rivercat]

Ron, what exactly did you replace?

 

[RonA]

I went from a 62/12 S300 to an SPS62 with the twins mods.

 

[Diesel Freak]

Is the drop in drive pressure on the top end worth the loss in streetability on the bottom?

 

[RonA]

My truck spooled very fast with the 62/. 7. Saying it takes alot longer to spool does not mean it is a lag pig. 25psi drop in drive pressure is conservative, it may be more than that. I lost about 8 psi of boost on top also. Less boost is a good thing when it occurs in conjunction with even lower egt. All at the same fuel settings. So to answer your question, I have 3 good gains versus one slight loss.

 

[Diesel Freak]

cool beans!!!

 

[Diesel Freak]

With regards to boost pressure, how far behind the SPS62 is the K31 once the K31 starts to make boost?



Also, what RPM does the K31 come off the peg with regards to boost?

 

[RonA]

The K31 moves off the peg at about 6 or 7 lbs right now. By 10lbs it is at 2lbs. At 20 overall it is running around 7 or 8. Rpm wise, I'm not sure. I don't have a tach, and I've only put on just a few miles. It is a bit slower than with the other S300. Fueling level is different now. 60 to 90 roll on hits 900. Runs about the same egt on flat ground, 600 at 65mph. Running up a fairly steep grade at 40psi and about 80-85 mph it runs 850. Boost has dropped around 5-7 pounds. At 58 or so psi I am running about 60psi drive, around 25 lbs on the primary. I set the gate on the SPS to open at 38 on the bench. Regulator limits it to 45 so the gate doesn't open all the way. I haven't had a chance to play with it much. It seems to come up into boost from a lugging situation pretty easily. That surprised me. I was a bit overfueled for the other S300, I could use a bit more with this one. At 1300 a set I'm going to make due with the injectors i have for a bit.

 

[BPonci]

At 1300 a set I'm going to make due with the injectors i have for a bit. [/QUOTE]





Right!! :-laf :-laf :-laf

 

[Diesel Freak]

The K31 moves off the peg at about 6 or 7 lbs right now. By 10lbs it is at 2lbs. At 20 overall it is running around 7 or 8. Rpm wise, I'm not sure. I don't have a tach, and I've only put on just a few miles. It is a bit slower than with the other S300. Fueling level is different now. 60 to 90 roll on hits 900. Runs about the same egt on flat ground, 600 at 65mph. Running up a fairly steep grade at 40psi and about 80-85 mph it runs 850. Boost has dropped around 5-7 pounds. At 58 or so psi I am running about 60psi drive, around 25 lbs on the primary. I set the gate on the SPS to open at 38 on the bench. Regulator limits it to 45 so the gate doesn't open all the way. I haven't had a chance to play with it much. It seems to come up into boost from a lugging situation pretty easily. That surprised me. I was a bit overfueled for the other S300, I could use a bit more with this one. At 1300 a set I'm going to make due with the injectors i have for a bit.

sounds very similar to how my setup runs... except that my primary never sees more than 18 psi, and I have not checked drive pressure yet

 

[BradyWilliams]

Thats interesting 1300. 00 a set for injectors. I wonder what you are looking at. Just wondering what injectors they may be?

 

[RonA]

DF.

My primary is only a . 7kg/sec charger. I'm guessing your primary may be larger than mine.

BrettWilliams. As far as the injectors go. I am not complaining about the price. I've had 7 sets so far. Only one guy delived a set that would idle. If you want to take a shot at it, great. All I ask is to get my money back if they won't idle. Your turbo is excellent. Can't wait to try out the pump you set up for me.



Ron

 

[Diesel Freak]

DF.

My primary is only a . 7kg/sec charger. I'm guessing your primary may be larger than mine.

BrettWilliams. As far as the injectors go. I am not complaining about the price. I've had 7 sets so far. Only one guy delived a set that would idle. If you want to take a shot at it, great. All I ask is to get my money back if they won't idle. Your turbo is excellent. Can't wait to try out the pump you set up for me.



Ron

actually my bottom charger is only . 72kg



and I am only currently pushing it to . 65kg