Ok I read the thread...I guess it is the HX40 VS the B-1. I was not sure since the PDR turbo could mean more than one turbo. <br><br>If you want a turbo to last through punishment and be a generally good compliment to the Cummins engine with the most durability...get the B-1 if your budget can support it.<br><br>Spool-up my be faster with the 40....but we all know what fast spooling turbos do...They choke more on the top end. Period. Some of the slower spool of the B-1 is due to the larger shaft size in the B-1. Its a trade off on the durability side. <br><br>Dyno comparisons wont yeild hardly anything of real value between the two turbos....Grab two turbos further apart to do comparisons with. <br><br>Durability testing will be tough as well on an engine dyno without many many hours, days, weeks of testing.<br><br>Perhaps bring more than one HX40 if you plan on drug testing. <br><br>Don~<br><br>

 

I never had a B-1 on my old dog 12 valve. Only the 40. I loved the performance in the lower and mid range. The top suffered a bunch though. I see on dyno graphs the top suffering some on the B-1 too. <br><br>If I had to tow and did not run over 450HP..I would say the HX40 is the better choice too. There is some stall in the b-1 turbo at higher CFM demand with lower boost levels. This is almost always a function of the turbo wheel design. Manufacturers cant make a wheel 100% efficient. So they try and match the wheel to the intended application. A wheel that stalls with the conditions you describe is always more efficient up top after the boost catches up the CFM demand. <br><br>A prime example is the Ford trucks currently turbod by Garret. They have terrible compressor stall when towing after a chip install or injectors. The boost is low and the CFM demand is much greater from the 444 cubic inch Navistar. They are trying to balance the needs of all the rpm ranges they can.<br><br>These two turbos are so close its a waste of bucks to test them on an engine dyno....Daily driving can tell you the B-1 is more efficient up top. More durable for long term and abuse situations, but has compressor stall at lower rpm range under towing conditions and suffers some low end response. These are slight differences.<br><br>A few good runs on the ol chassis dyno with a good shot of nitrous or a heavy fueled diesel run can &quot;pop&quot; a 40 in short order though. <br><br>I guess it all comes down to who you like between the two vendors, your budget, and the conditions you use the truck for most.<br><br>Don~<br><br><br><br>

 

Don,<br><br>We are comparing spoolup and airflow because a previous person who posted said that the B-1 spools faster.... Faster spooling turbos do not always choke off air. In fact I would bet the B-1 and especially the Kwickspool model will be more restrictive. Shaft and wheel size and weight have huge impact on spoolup, along with tight exhaust housings..... How do you think KSB-1 spools faster? Its a tighter exhaust housing thus increasing backpressure.<br><br>Nobody is disputing the durability of the B-1. Heck I feel it is the best turbo out there for guys abusing them or running drugs. But for the daily driver that has below 500 HP and not running drugs then I feel the PDR-40 is a better choice for drivability. As for making HP the dyno testing I have done shows both turbos to make almost identical HP when used on the same truck.<br><br>Doug

 

Generally you are correct in saying that tighter housings equate to more restriction. This is almost universal.<br><br>I just dont want everyone to think that this is the only factor. Turbine wheel design can and does in some cases, make a marked difference in restriction. Speed of the exhaust gas, turbine blade design, and the volume of gas the turbine has to handle are all important. I have seen engines use the same wheel and change housing sizes and not change in performance at all. I have seen larger housings with a more restrictive wheel design ( generally designed for a faster spool time in stationary engines ) do worse than smaller housings with a better flowing wheel. There are many variables that many seem to overlook.<br><br>I have seen a timing change make one turbo lay down on power and one pick up power. This is directly related to gas expansion, the timing of such events and wheel type/style. And has much less to do with housing size. <br><br><br>Don~

 

Don:<br><br>You and I have discussed the Piers HX-40 before and I think<br>we both agree that for towing and &quot;street use&quot; it is a better<br>turbo for &quot;our dog 12 valvers&quot; as you put it!! <br><br>I agree with Doug though that &quot;faster spooling turbos do not<br>always cut off air!&quot; On my 12 valve, the Piers HX-40/16 spools up faster than either of the two B-1's PERIOD!! Doug<br>has ridden in my truck with all of the turbos and he can <br>testify to that fact. As far as durability, you guys are <br>probably right, with NOS and or propane the B-1 is probably<br>better, but,.........Doug did have some problems with his<br>B-1, so it is not completely bulletproof as some think. As we<br>all know, ANY TURBO can blow up with the right conditions<br>etc. I also agree with Doug on the dyno testing. I have<br>posted the differences in the numbers with the Piers HX-40<br>and the B-1's on my 96' 12 valve. These numbers were<br>from a Mustang Inertia Load Dyno and IMO act as a GUIDE<br>to someone wondering what they will gain on a given truck<br>with a certain turbo. On my 12 valver, the H.P. increase is<br>very slight from the Piers HX-40 to the B-1 as Doug has <br>pointed out. <br><br>--------<br>John_P <br>

 

[quote author=Don M link=board=7;threadid=15479;start=30#148317 date=1055366692]<br> a heavy fueled diesel run can &quot;pop&quot; a 40 in short order though.[/quote]<br><br>Been there done that X's 2 on #2 only