Miata Turbo Forum - Boost cars, acquire cats.

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-   DIY Turbo Discussion (https://www.miataturbo.net/diy-turbo-discussion-14/)
-   -   my miata's back... slower :( AVO beats BEGI (https://www.miataturbo.net/diy-turbo-discussion-14/my-miatas-back-slower-avo-beats-begi-10817/)

Pitlab77 06-27-2007 10:18 AM

http://www.avoturbo.com/avo_guides/d...2/DSCN3378.jpg
http://www.avoturbo.com/avo_guides/d...2/DSCN3383.jpg
http://www.avoturbo.com/avo_guides/d...2/DSCN3388.jpg

Markp 06-27-2007 12:58 PM


Originally Posted by fmowry (Post 126518)
C'mon Jason, everyone said the BEGI manifolds were the best thing since sliced bread. Stephanie has touted their "superiority". I've said in a few threads, TEST THE MANIFOLD TO OTHERS on a dyno and datalog before you claim victory. Seems like a simple premise to me.

Too many BEGI lovers here.

I don't care about the math behind the design of a part, I want to see the results on a dyno.

Frank

LOL, I wonder why people love them. Maybe it's the fact that they genuinely care about their customers. While Stephanie is certainly learning alot and coming into her own, I don't think that you need to target her. You should aim your criticism at Corky, as he is the one who believes his manifold is better than the competition. Stephanie is merely the person we see in public on a more common basis.

So here we have a manifold that flows better than the BEGi one. Good enough for me. I do think the BEGi manifold is better than the FM manifold. I suspect that I will lose some power from my Ghettocharger manifold to the BEGi one, I would be surprised if I didn't. I do expect to gain a factor of reliability though. Jason got a manifold that was easier to install. Does that count towards superiority? Perhaps not, but it is something to consider as well.

There is one other possibility, although I am sure Jason has already looked at this. The new manifold may benefit from different tuning and that could be playing a factor in the way the turbo and manifold are performing. Either way, it looks like the AVO manifold might be the better manifold.

Mark

Braineack 06-27-2007 01:08 PM

i wonder how long that Copper RTV will last?

RusMan 06-27-2007 05:28 PM


Originally Posted by Braineack (Post 126633)
i wonder how long that Copper RTV will last?

28 seconds, haha.

Anyway, that's the same manifold I have. It mounts the turbo a lot lower than begi or any other manifold I've seen. I can confirm that it is a b*tch to install, the bottom bolts are impossible to reach and I had to replace the nuts twice because I stripped them both times I was taking it off. I cannot comment on the flow because I never had another manifold

JasonC SBB 06-29-2007 02:00 AM

Maybe the reason for the AVO's superiority is that the passages are narrower... keeps velocity thus kinetic energy up.

Markp 06-29-2007 07:44 AM


Originally Posted by JasonC SBB (Post 127288)
Maybe the reason for the AVO's superiority is that the passages are narrower... keeps velocity thus kinetic energy up.

It's quite possible. Getting heat and velocity in there is key to making it spool. We often used smaller diameter header pipes because they spooled much more nicely than the large pipes and we lost no real power from them (sub 300 RWHP.)

Mark

Crimson 07-01-2007 07:43 PM

Can you buy the AVO manifold by itself in case you're planning on a DIY kit?

greddymx5 07-01-2007 08:30 PM

http://www.avoroadster.com/avo/html/mazda/mazda.html

Yep 1.6 mani is for sale... (aus dollar)

joeyb 07-01-2007 10:00 PM

US$594.88 for the 1.6 AVO manifold, based on AU$700

JasonC SBB 07-01-2007 11:59 PM

Got some proper spoolup datalogs done, with some numbers with the AVO. 2nd gear, flooring it at 1500 rpm, same flat road, ambient within 6°C of each other. Full boost is 170 kPa.

Remember this is 2nd gear, it takes all of ~4sec to go from 2000 to 6000 RPM

RPM AVOkpa BEGIkpa
2000 117 112
2500 136 128
3000 161 145
3277 170 159
3450 175 170

Huge difference around 3000 rpm - 2psi - this is why the car feels much soggier shifting at 3000 rpm. On a bad day the AVO never felt this laggy. :(

Crimson 07-02-2007 12:09 AM


Originally Posted by joeyb (Post 127927)
US$594.88 for the 1.6 AVO manifold, based on AU$700

Ouch, I was hoping for something closer to the price of the BEGi manifold. Say around $400? I also like the fact that BEGi will put a custom flange on the manifold for you too.

JasonC SBB 07-02-2007 12:35 AM

US$ has been dropping like a rock. In 2000, I got my whole AVO kit for US$2000. Gotta thank the Federal Reserve, the gov't, and the war for that one.

magnamx-5 07-02-2007 12:53 AM

finnally i found the fabled avo site. anyone know the conversion for kwh to hp. Edit damn only 200 whp at 13 psi what is wrong with there car?

RusMan 07-02-2007 03:24 AM

I made 210whp at 9-10psi, so their car is messed up I think.

JasonC SBB 07-02-2007 08:30 PM

No comments on my HARD data?


Originally Posted by JasonC SBB (Post 127973)
Got some proper spoolup datalogs done, with some numbers with the AVO. 2nd gear, flooring it at 1500 rpm, same flat road, ambient within 6°C of each other. Full boost is 170 kPa.

Remember this is 2nd gear, it takes all of ~4sec to go from 2000 to 6000 RPM

RPM AVOkpa BEGIkpa
2000 117 112
2500 136 128
3000 161 145
3277 170 159
3450 175 170

Huge difference around 3000 rpm - 2psi - this is why the car feels much soggier shifting at 3000 rpm. On a bad day the AVO never felt this laggy. :(


JasonC SBB 07-02-2007 08:32 PM

THIS looks like a nice homemade turbo header.
Note how the pulses would flow INTO the turbo.

http://us1.webpublications.com.au/st...6/2658_8lo.jpg

Ben 07-02-2007 09:23 PM

does the AVO hold the turbo down a little lower? That would result in a straighter, and possibly slighly larger diameter, downpipe. I've always thought that the restriction after the turbo, not before, was the primary concern.

Ben

Braineack 07-03-2007 08:52 AM

I think the main problem when you look at the BEGi vs. the AVO is that the AVO in the least slightly angles the pulses into the turbine....the BEGi even with it's "directed pulse" wall, still has 1 & 4 pointed towards each other....not even ever so slightly into the turbine. Hitting the pulse wall will angle it in, but then that's another 90° the pulses have to travel.

I'm confident that Corky, if backwards compatibility wasn't a concern, even with a cast manifold, would have designed it slightly different.

JasonC SBB 07-03-2007 03:58 PM

Yes the AVO mounts a lot lower and there's a nearly straight shot from #3 into the turbine (funny the turbo mounts rearward despite lack of space for the downpipe). It also appears that the curves for #1 and #4 are gentler. On the BEGI the runners come out from the ports a bit before turning sharply, to make room for wrenches. On the AVO they begin curving immediately, thus the gentler radius. There is also a slight turn-in into the turbine for #1 and #4... but of course #1 and #4 still "look" into each other.

JasonC SBB 07-03-2007 04:01 PM

I keep looking at this ETD shorty manifold and getting a woody. Look how beautiful the flow is into the turbine:

http://www.etdracing.com/products/manifolds/miata1.jpg

I called them and for an add'l $100 they can custom build one in 3 weeks using 1.25" tubing (inst. of 1.5", for spoolup), with a T25 flange. The extra $100 is because the runners need to neck down more for the T25's narrower entry.

They said they plan to stop making it at some point because it's less profitable than their other stuff. :(

I visited the muffler guy who built my custom exhaust and he can modify my BEGI downpipe to work with the new manifold for $120 to $300 depending on actual time, and ~2 days.

So............ should I leap in?


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