The problem is that not all cars are in the same shape.
And with comparisons like this we can not expect that.
Most early dynos of the PE1420s were done on cars that were not in a great a state of tune, that combined with all the "quirks" these turbos had, led them to get a bad name.
As more dynos come out from people with properly set up engines I think your mind may start to change about their potential and spool up characteristics. But, I am not sure if it will really make a difference to most people as they seem to be "written off", perhaps (we will see) a shame.
That is really all I have to say about the PE1420's specifically."Turbos like sport 500's spool up almost as fast as stock, as seen in the first graph on that page. The GT2530's, while often credited with having "like stock" spoolup clearly don't have spoolup like the stock turbos. Bernie even goes out of his way to state that."
2530 "unknown" from that chart has spool that most would agree is very stock like.
"all turbos of a specific model will be within a pretty small range."
I think the range (between unknown and daryl) is pretty significant in the 2530 chart (also the one with the most entries).
On just about all of the charts on there, the lag is directly proportionate to the power that the turbo is capable of putting out. That's because most turbo upgrades are spec'ed as close to optimally as they could get it. The only exception is the T25/T28's which have a ton of lag and don't make good power either, and as we all know that's because they were not designed properly to begin with. For all the others, the lag is proportional to the power. Even the new Sport 530's have slightly more lag than the old Sport 500's, and make slighly more power.
In fact, you don't see any well designed turbo on there which produces more power AND has less lag than another type. That's the stuff that hype is made of but unfortunately reality doesn't coincide with the hype.
I have two issues with your points here. 1)First you say that T25/T28 doesn’t count and I agree and understand but for the same reasons they don't count (poorly engineered/matched), other turbos could be better matched/engineered and cause the opposite reaction (great spool and top end vs. the T25/T28 poor spool and top end). The only 2 turbos in that comparison are even using ball bearings are the Sport 530 and the HKS2530 (the others are very old designs). And of those neither have the latest version of the turbine and compressor wheels from garrett. My understanding is the wheels in the 530s are all old (not sure on the details there) and the HKS2530 has the newest turbine wheel (76 trim GT28 turbine wheel), but still has an older compressor wheel (63 trim T28 compressor wheel vs high B-Width 62 trim GT30 wheel -GT28RS). And the result? The turbo with the newest technology comes out looking the best(HKS2530). It can achieve very near stock spool up but with much greater top end. As an engineer type I'm sure you can appreciate the gains that can be made from more efficient designs. The fact is that more efficient compressors and turbine wheels with more efficient bearings will create a more efficient turbo. Efficiency can better spool, or better top end or even a bit of both. My second point:
2)To automatically assume because someone has X turbo their lag will be Y is not fair either. There are many places in our engines where we can extract more flow to improve the lag of our turbos (manifolds, heads, ICs, exhaust just to start). You might be amazed at the differences increasing the flow in ALL these areas of the engine can make. Now you are not cheating here if you made all those necessary mods to a stock turbo engine it would spool faster too. But working these areas (and other areas of the system) can yield you the necessary XXX RPM (in spool up) to get certain (most likely modern) turbos to achieve stock or stock like spool up. I don't mean to go on a rant here and on principle you are right that you don't get something for nothing. Better top end and better spool is/does sound like marketing BS. But, I think you too quickly apply that common sense reasoning, without fully considering the age of many of the turbo designs we are looking at, and the engineering improvements that have been made since. I've said it before and I will say it again. In the future the only reason I can see for someone to go with anything other than a GT550-R(/PE1420) or GT675-R (type turbo) would be price. Sport 500 is a good value because its performs better than stock and is made of components that are old and cheap, but it is NOT the best turbo design for our cars.
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