Originally Posted by paul_dezod

Why such generalized statements toward T3/T4 turbos? They all are not laggy what so ever. Some oversized or improperly matched ones with larger A/Rs may very well be. With a properly selected A/R, and exhaust housing, one can acheive a great blend of power, spool & drivability.

In actuality, I feel the tC is really pushing that 16G too hard. In some cases on some lower boost, it is close to the choke point. From some quick and dirty calculations, with a pressure of 10 PSI (1.68 Pressure Ratio), that turbo at 4000-6000 RPMS just continues to plummit from a peak efficiency of 71% at peak TQ and falls off to a bit over 60% by redline. The fall off in efficiency means decent temped compressed air @ peak efficiency then as it falls (RPMS increase here), to really hot condensed air making the intercooler work twice as hard to cool that air. The intercooler only has a limited amount of cooling capacity (most are 75%), this means that your intake temps just got a bit hotter, which in turn means you are getting less power.

Also, the 16G has an Inducer of 1.903" & Exducer of 2.675", turbine exducer of 1.935" & major of 2.205". This turbo with these specs reaches your peak CFM at 25 PSI. What does this mean? It only puts out about 27lbs/min (really rough calculations). Yes out put will increase as PSI increases, but how many people on here are going boost past 15 let alone 25? Probably 5-10%.

I feel the generalization of T3/T4s being too laggy comes from a scenario like the T3/T04E 50 on the tC. The TQ curve is not really that flat, and notice how 'hill like' it is, a mountain if I may:


A flat curve means more area under the curve, which means more useable power.



Note how flat ours is. Now just to make a bit of a comparison and make them seem more alike, I will truncate the T-netics graph from 3700RPMS or so on....





So all in all, our turbo is a T3/T4 and spools failry quickly due to several attributes in the system including turbine A/R. Our peak TQ is made at 3800-4000 RPMS, which is the same as almost any 16G (which is also supposed to a fast spooling smaller turbo) if you want to judge a turbo's merit by when it begins to make boost. That is hardly a good measure.

Cost, build, power goals (I want 5xx HP), power distribution (I want some mid-range and top end vs low to mid-range), warranty info and how well it works with what your doing.....

Originally Posted by MIAPLAYA

You need to remember that tuning plays into this tq curve a lot too. The drop in tq on this graph is due primarily to a reduction timing at the top end to keep things very safe... This is pretty typical of out of box Turbonetics kits. They pull a LOT of timing top end to keep the AFR safe with 91 octane we have in Cali at the top end...

Originally Posted by paul_dezod

As well, our tune is VERY conservative. Quite rich and some pulled timing too.

Originally Posted by MIAPLAYA

I'm not saying you didn't. What I'm saying is that I think Jhame pulled a LOT more timing top end then you guys did. If you ever tried tuning on 91 you'd know what a biatch it is to keep an 11:1 AFR top end. Our gas in cali SUCKS.

Originally Posted by paul_dezod

Pulling too much timing will result in UBER high EGTs which stresses a lot of equipment, so that could be veyr dangerous.

Originally Posted by MIAPLAYA

I'm not sayng he pulled TOO much timing. Just that he HAD to pull more then you due to the gas we have here. The 91 here is barely even that. EGts are right in line where they should be. But to keep an 11:1 he had to pull more then you did. Believe me in Jhames 20 years as a Mechanical Engineer designing, building, and tuning turbo kits and race cars he's pretty well versed in the art of fine tuning and would not put something out that was unsafe.

Originally Posted by paul_dezod

I am not doubting his skills, just making people aware of the results of trying to create an auora of safe in tuning.