Originally Posted by 07VTRex
i want to chime in an say that i am having similar experiences with my DOM 1.5xtr. I have had almost the identical discussion with Ron, as he also tuned mine.
I want to say that this turbo is not all its cracked out to be, and i like many others have fallen for topspeed's propaganda on this turbo.
While i like this turbo better than my VF, it didnt live up to my expectations. Topend is definetly better, i enjoy the linear power delivery, but the low end is gone, and i am starting to miss it. It became immedietly apparent when pulling a VF suby locally and me being suprised i didnt smoke him
I am hoping that meth injection is going to bring this turbo to life, and get close to the results we have been lead to expect from topspeed's testing.
*Ron, is there anyway you could add my dyno plot to the above with OP and northmans to get a 3way comparo going? I am just curious as well as to how mine stacks up.
i am REALLY hoping meth can get me in the 340-350 range, with hopefully more improvement in the midrange torque. Just hope the stock block will hold that much, we will see
I agree that TopSpeed's testing was a little bit misleading for this turbo. They did not show the boost plots, but in the posts it is mentioned that they were all done on high boost. Usually in the 25-28psi range (on E85). This turbo on pump gas is going to have considerably more lag than a VF, but unless you push it to higher boost, you're really not going to see the payoff. At 20psi or so, you're going to lose a bunch of your powerband, and only gain a small amount up top.
I have the 20G XTR, which is very similar to the Dom 1.5XTR. Boost comes on considerably later than a VF (~600rpm's), but the low/mid range torque really isn't that far behind. But, since I run mine at much higher boost, I get a really strong midrange torque peak, and the top end holds on reasonably well. If I had the same spool, but only was making low/mid 300's WHP (ie. pump gas and 20psi), then I don't think I'd be very happy with the setup.
I think Phatron might be right that this turbo isn't the best on a 2.5L. Especially not for one that is on pump gas unless you're willing to take the risk with a more aggressive tune. With E85 and more boost, I think it does well compared to the other turbo's of similar size, but the Dom 2.5 XTR also seems like a good option for someone wanting more top end.
EDIT: That 20G XTR log from the plot above does about 440WHP in Airboy.