Care to give my logs a critique? As you can see my spool is terrible. But I think it's more a limitation of the crush-bent DP. Any areas of improvement? Here is the dyno of these pulls. Run 3 is with the boost turned down to 11psi, it's in blue.



I've noticed that the boost drops a bit when it reaches the target, which means I need to play with closed loop boos control some more. That will help with the torque dip once spooled. Do I need some more timing during spool up?

 

you have a 1.6L with a crush bent DP.

fix both those things.


you are pushing the limits of your rods, fwiw.

 

That's why I turned the boost down for the third run. I've read 250wtq is the limit, and not 250whp. Which is it?

I just added new wheels and tires and a roll bar, so I'll need to find a good deal on mani/dp. Miata funds this winter are already tight.

This much power shows that my manifold is good, right? So really, I just need a high-flowing downpipe? I'll see what some custom shops around here charge.

 

do you use HP to push your pistons down?

 

fyi the earlier in the rev range that you hit the 250tq the higher probability that a rod calls it quits and promptly exits out the side

 

I know that, but spooling at 4800-5000 sucks for autocross. Trying to improve that as much as I can. I was not expecting 250+hp and that's why I turned down the boost. I don't want to test out the 250wtq/250whp limit, whichever it may be.

 

everything you can do to improve flow/efficiency at this point is only going to help you.

 

The question is then, do I want to spend ~$1000 for a bottom/side mount and DP which will have better spool than the top mount I have now, or spend ~$500 for just a big mandrel bent DP and stick with my current top mount manifold that is rock solid.

I'm not starting over with a 1.8L engine any time soon. I have plenty of power. More than I need actually. Spool is what I need now

 

post pics and details of your setup so we can see what you're actually talking about

 

Deets in sig. Here's the DP:
https://www.dropbox.com/sc/ft8fqswfo8uaezz/-zvr1eOleR

 

that looks awful. and your sig still doesn't show us your manifold. based on that downpipe though, I'd say yes there is quite a bit of room for improvement in your setup

 

Like we said the other day. I'm sure if you had a decent flowing mani and downpipe your motor would have probably went pop on the dyno. lol

 

LOL, that downpipe is really bad. Whats the manifold look like?

 

A stock 1.8 can't make any more power than a stock 1.6, they both break at >~230wtq. The difference is the 1.8 spools better.

 

https://www.dropbox.com/sc/drn90wccl5j0twv/5RA9FDy8Zy

There's the manifold. Sorry I don't have great pics installed while at work.

 

Is that one of those old HKS units? The manifold actually looks much better than that downpipe, so I'd address the downpipe first and foremost.

 

It is. However it mounts the turbo so damn high the DP is pretty much guaranteed to be spaghetti. Makes me wonder if it's worth it...