How close is too close when reading compressor map

[[Freemantle]]

Okay, so I've got my money set aside. It's time to plan out what I am buying to boost my H23. Right now I'm at square one: Compressor Selection. I've graphed my required flow for my setup on many different trims and housings.

My question is, when are you "too close" to the surge line?

Some compressors have a spool-up a good distance away from the surge-line (as much as 7lb/min). (T25)

Other compressors parallel the surge line at spool up by a mere 2lb/min. (T04E 40-trim)


Still yet others lie barely to the right or directly on the surge line during the spoolup. (60-1, T04E 60-Trim)

Now, I'd love to run one of the lower turbos. The great thermal efficency at mid to high revs is a good thing. It will give me room to upgrade.

The T25 has good thermal efficency on the spool up, but gets very low near the top of my tachometer (almost 60% at some points). This is uber no good.

Is the T04E-40 the best bet for me?

 

[D See 2]

loco and pissedoffsol will have good info for you...

 

[posol]

the t25 is out of the question. its way to small to be truely effective on a 2.3

the 40 trim t403 is also kinda low...

the 60-1/S-housings won't give you the spool you want

t3/t04e .63 / .63 is my recomendation

 

[[Freemantle]]

Okay, I just plotted the line for that compressor. The roughness of it lies directly on the surge line. This is okay?

 

[Loco Honkey]

No. Get as close to Efficiency Island as you can. That's the sweet spot of the turbo. Surge line is the worst place you can be near.