Thanks Mark. Mike B. also has A28s and I think he just broke 6 sec. It seems A28s flow better than vtgs at least on the surface.

 

I have some upgrading to do before she breaks into the 5's. I am on stock intercoolers and 300 cell cats, so those need to go and I need a race gas tune. Then maybe into the 5's.

 

I have the same mods, or less, than you, only I have 18g's and the Meth. I just got into the 5's...barely...I am finally going to do intake piping and IC's now...

 

Just finished my inlet pipes, nice difference, spool quicker and really hear the turbo's spooling.

 

Nice!!! What a b*itch job with the engine in...but it looks like it can be done...Old piping and plenum is out, just ran out of time last weekend. Hope to get back to it after the holidays...

 

A few questions...

1. What exhaust and cats are you running?

2.What boost are you running?

3. Do you use a boost controller?

4. Do you have a race gas tune?

 

1. What exhaust and cats are you running? FVD sport exhaust. Not sure, but guessing 100 cell cats.

2.What boost are you running? 1.3bar I will see 1.4 in the cooler weather. I need bigger wastegates to up my boost I think.

3. Do you use a boost controller? NO. My tune dictates my boost.

4. Do you have a race gas tune? Nope. Just 93 pump and 100% meth. We did try a race gas and 50/50 tune, but it turned out to only make ~20 more whp, so I stuck with the pump/meth. I'm hoping bigger piping and IC's will be a noticeable improvement.

 

This makes a case for rwd vs awd...

 

I am RWD now too and I think it helps, as well as the LWFW.

 

Great info. Thanks!

 

You really have to push an upgraded VTG to the limits to get it to perform the way our custom 28's run, and that is why we started running the custom A28's, because they spool just as fast but provide another 100whp worth of flow on the top end, at least on our P800 package... We don't like running anything to the limits. Safe HP is comfortable HP...

 

can ya'll post some dynos?

 

That certainly seems to be the case. If I were to do it all over again, I would think twice about upgrading with vtgs. There some better options out there although the spool time for upgraded vtgs is outstanding for low-mid end. It seems the current vtgs has limitations and could benefit from a redesign of the turbine. It's still a great turbo for all around purposes.

 

what plenum are you going with? IPD

 

Mark,
You have forgotten more about turbos than I will ever know!

But the faster A28 cars are almost half a second quicker than the faster mod VTG cars in 60-130.

Maybe from your perspective of large turbos they are similar?