greddy turbo spool up questions
 

hey guys, ive been running my miata around for about a week now with my stock greddy, with the exception of a intercooler and bov. its like 25* F in reno so im able to run advanced timing of 9* without bipes or anything to retard timing under boost.

i drove my friends miata around when i was down in LA for the weekend. hes running a similar setup with turbotony dp, and rsr gt2 exhaust. once he gets past 3k rpm, turbo spools and pulls very smoothly from 3k -> redline.

mine on the other hand, will begin to spool around 3.5k (maybe 3psi) then once i hit 4-4.5k it will pick up the big 5psi and throw me to redline. Im running stock greddy dp and stock exhaust. The turbo feels like its a huge turbo or something due to the way it kicks in later. is this solely due to my restricting exhaust ?

im in the market for a new exhaust, but im torn on which to get.... i love my friends rsr.. but its discontinued now... im a fan of the apexi n1, but it looks very similar to stock.. with a 3" tip.

should i buy a catback system with a midpipe ? or buy a turbotony dp first ? even if i buy a catback system.. they all come with the midpipe which will be replaced by the turbotony dp right ?

any advice is greatly appreciated guys, thanks ahead.

Scott

nah on Miata's they have a 2 peace header/dp so it goes DP -> 2nd DP thingy - > Cat -> Mid-pipe -> Axle Back so the Turbo Tony DP will get you to the Cat then you'll need a bigger cat and Mid-pipe and axle back.

might as well do it all at the same time if you're up under the car. get in touch with tony, he can also provide a high-flow cat. then if you need a larger exhaust on a budget check out the enthuza stuff.

I have the same set up now with the base kit running 10BTDC, on 98 Octane fuel @ 22Deg. Celceus. Turbo starts around 2800rpm, power comes around 3300rpm and up. I have been waiting for Tony's reply about this DP for 4 days, I am patiently waiting still.

I dropped 400-500rpm when I replaced my pea-shooter stock "midpipe" with a custom one made at the local muffler shop.

so i guess exhaust should b making a difference.

but does that also explain my kind of weird surging with the boost ? not enough room for the exhaust gases to pass the turbo and spool faster, but at higher speeds/more rpm air pushes its way out the pea-sized stock exhaust?

too much backpressure to allow the turbine to spin as quickly. Look at dynos from modified greddy kits vs. stock kits. you'll see a big difference in initail power curves. Making 100hp at 3.5k as opposed to around 4.5k. Other factors can be involved as well, but in general, those greddy kits benefit greatly with a new exhaust setup.