Miata Turbo Forum - Boost cars, acquire cats.
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Miata Turbo Forum - Boost cars, acquire cats. (https://www.miataturbo.net/)
-   Engine Performance (https://www.miataturbo.net/engine-performance-56/)
-   -   Forged pistons & turbo lag reduction (https://www.miataturbo.net/engine-performance-56/forged-pistons-turbo-lag-reduction-80913/)

bcrx7 09-12-2014 01:12 PM
Originally Posted by concealer404 (Post 1166694)
Well if you were waiting for boost, wouldn't that actually be a threshold issue, not lag? :rofl::fawk::giggle:
This is at like 6000rpm, they are pretty odd! :vash2::dealwithit:

concealer404 09-12-2014 01:32 PM
Originally Posted by Leafy (Post 1166697)
No for realz, 70's turbo cars, well above the boost threshold, its kind of like punch it and pray that in a couple seconds (well it feels like a couple seconds) when the turbo actually spins up that you're straight enough that it doesnt snap sideways.


I know this... i was making fun of the maybe intentional omission of "full" before boost.

You guys ruin everything. :rofl:

Leafy 09-12-2014 01:37 PM
oh.

guttedmiata 09-12-2014 04:26 PM
Originally Posted by bcrx7 (Post 1166692)
You get on the throttle mid corner hoping by the time you are hitting the exit you have boost!
Which is exactly what we had to do with the greddy setup on the 1.6 when we got the car. After changing the intake piping and the entire exhaust from the head back to dumping right after the drivers seat, we only had to floor 2/3 of the way through the corner. Still sucked. It's fixed now though.;)

bcrx7 09-12-2014 04:37 PM
Originally Posted by guttedmiata (Post 1166760)
Which is exactly what we had to do with the greddy setup on the 1.6 when we got the car. After changing the intake piping and the entire exhaust from the head back to dumping right after the drivers seat, we only had to floor 2/3 of the way through the corner. Still sucked. It's fixed now though.;)
Yes, the wrong size turbo or issues with the system will cause lag. The main reason for the diesels lag as I mentioned. Most diesels will get more power/torque and most likely better fuel milage just upgrading exhaust to a bigger/free-flowing system. Not sure what the restrictions are that makes the car makers put crappy systems on. Most likely noise.

guttedmiata 09-12-2014 05:16 PM
Had massive free flowing exhaust on my truck. Laaaaaaaaaged anyway. Unless I could brake to build boost, I would always loose the jump or hole shot........and then smile as I powered past my competitor.

Twodoor 09-12-2014 06:43 PM
Originally Posted by thenuge26 (Post 1166617)
Haha I bet it is crazy, especially compared to the fiesta I'm DDing now, as the NYT writer said the gears are so far apart they need counseling.
I'm going to be at Cozzolino Motorsports (SE Indianapolis) around noon Saturday to dyno the car. Need to make sure I am not running too much boost :) My goal at this point is to make the most power I can while not going more than around 230 to 240 torque at the wheels. According to "virtual dyno" I am there... but I need a real dynojet to back that up before I trust it.

Keith

PS: Dynoing in 5th just seams weird!

bcrx7 09-13-2014 12:04 AM
Originally Posted by guttedmiata (Post 1166777)
Had massive free flowing exhaust on my truck. Laaaaaaaaaged anyway. Unless I could brake to build boost, I would always loose the jump or hole shot........and then smile as I powered past my competitor.
This is off the line?

guttedmiata 09-13-2014 08:55 AM
Originally Posted by bcrx7 (Post 1166879)
This is off the line?
Or from a roll. Which was lag.;)

bcrx7 09-13-2014 12:24 PM
boost threshold hahaha

sixshooter 09-13-2014 02:28 PM
Some of the old Chrysler K-cars were really unresponsive with their old T3 turbos. A buddy had a little convertible that you could stomp the throttle and have time to say "wait for it" before it would make power and torque steer you towards the ditch!

bcrx7 09-13-2014 05:03 PM
Well at least the K-cars you could disconnect the wastegate and make some few infinite-PSI runs down the track! K-vans are nice sleepers haha

Twodoor 09-13-2014 07:04 PM
Originally Posted by thenuge26 (Post 1166569)
Even concealer's gt2554 car has lag. We measured it on the datalog, it was like .25 seconds :party:
Having taken a ride in Ben's car this inspired me to do a highway data log for lag documentation. On my GT2860R doing a steady 80 mph on the highway in 6th gear (about 4300 RPM, well above boost threshold) from going WOT to boost hitting 9.5 psi was .366 seconds, (this is where my wastegate starts to open) and another 3.44 seconds to hit set pressure of 11.5 psi at .73 seconds after going WOT... but that is relying on boost creep to get from 9.5 psi to 11.5 psi.

I will have dyno sheets up in my build thread soon, just have to re-size and post them :D Then it is off to the 1/4 mile track Sunday.

Keith


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