na turbo recommendations..

[mx52nv]

yeah iv'e heard they are quite a good manifold. thanks for some real world figures to go with it!
atm it has 140rwhp at 7psi ...so im looking for 200+

the reason for external gate is better/accurate control, if im doing a custom mani i might as well put one in and the most obvious....an mx5 with a screamer pipe

so the main reason now is room for a decent size dump....any pics?

cheers

Hi buz 138,
As I mentioned before, all the B6 AVO kits I have done get aorund 230-240rwhp with an upgraded fuel system, (2.5" and above) exhaust and an aftermarker ECU system. If your goal is 200rwhp then why are you not just tuning the car for 15 psi (or whatever boost will get you 200rwhp)? If the boost curve is not great then there are cheaper options like changing your actuator, boost solenoid valve, getting an electronic boost controller or a good stand alone ECU.

Put simply, I really do not see the point of changing the manifold and adding a wastegate to your set up. I suppose I am coming from the perspective of "if it is not broken, why change/fix it"...? Especially in your case, where if you added some forged connecting rods to your bottom end, upgraded fuel system, a good ECU and dynotune, I can see you hitting (a lot more than) your target without touching the current turbo kit hardware.

Of course, if you are wanting to do this for pure fun (noise) factor, bragging rights or just because you can then just ignore my spew above.

Oh and if that is the case, I have a slightly used (less than 9,000km) GReddy Exhaust Manifold with the tuned length runners and external wastegate flange for sale. Terry from our club has just over 170rwkw/232 rwhp on his MX5 with only B6T (Familia) factory pistons. PM me if you are interested.

Les @ MX5 Shop

[buz 138]

nah mate its cool i see exactly where you are coming from!
...but my only concern ( as stated previously) is a decent size dump ( the avo "angle" one looks sooooo restrictive and small)
...i did a google for some pictures but found nothing relevent.
...so my reason for external was.. if i need to move the turbo away from the fire wall (forward) to get a dump pipe in i might as well make a good manifold and plumb in an external gate while it is all apart.
i really hope i can leave it where it is actually but just need to know about the dump.

it already has a walbro pump, malpassi and the stand alone miata link ecu (could only get 140hp as the standard injectors maxed out)
so shouldn't need too much more for some boost

[mx52nv]

...but my only concern ( as stated previously) is a decent size dump ( the avo "angle" one looks sooooo restrictive and small)
...i did a google for some pictures but found nothing relevent.
...so my reason for external was.. if i need to move the turbo away from the fire wall (forward) to get a dump pipe in i might as well make a good manifold and plumb in an external gate while it is all apart.
i really hope i can leave it where it is actually but just need to know about the dump.

it already has a walbro pump, malpassi and the stand alone miata link ecu (could only get 140hp as the standard injectors maxed out)
so shouldn't need too much more for some boost

Hey buz,
Okay if the dump is the issue then here is what I did: a custom 2.5" dump (seperate internal wastegate channel) and a mallet for the offending firewall. Works to over 300rwhp!
Good luck with it all!
Les

[buz 138]

beuty!! thats the info i want!!
.. so cut the lip and a but of light "cough" mallet work will do the job!?
and only 2.5 inch is enough? what about the rest of the exhaust? i know you have 2.5 but a few things i have read say go 3inch?

[bark]

Les, I have a greddy td05 kit also and I'm wondering what dump pipe and exhaust size I should run. At the moment I am simply running a dump pipe that is the same size as the td05 exhaust flange... I've got the B6T pistons and rods and am getting 150rwkw at 16psi. I'm thinking the lower comp and perhaps restrictive dump/exhaust maybe where I have fallen short of Terry's 173rwkw??

[mx52nv]

and only 2.5 inch is enough? what about the rest of the exhaust? i know you have 2.5 but a few things i have read say go 3inch?

Hey buz & bark,
For maximum horsepower and a more top end power delivery then a 3" turbo back exhaust system is optimum.
This is great for circuit racing as you are able to keep the revs up in the powerband.

For response and more low to mid-range power delivery then a 2.5" turbo back exhaust is a good balance.
This is great for short distance racing such as motorkhanas, autokhanas or sprints/hill climbs.

This is obviously depending on the size of the turbocharger in use and certain other factors but the above applies to B6 turbo powered MX5s.
Many turbo back exhaust applications fall into the 'bigger is better' category as users chase all out horsepower.

Hope this helps with some of your decision making.
Les

*edit*
Just saw bark's post and I guess the the obvious question that must be asked is if the figure was on a Dyno Dynamics Dynamometer in Shoot Out Mode in 4th gear (1:1 on a 5 speed gearbox) and 37psi tyre pressure? If not, then maybe book it in to your nearest one before you make changes. The afore-mentioned specifics are the conditions that Terry ran his MX5 on the dyno that day.

If it is on a DD Dyno then could you please confirm the diameter of the whole exhaust system (i.e. 2.5" dump, xxx mid pipe & xxx inlet to muffler)?

As an ex-Trust distributor, I am fairly certain the dump & front pipe that came with the GReddy TD05 external wastegate kit was pretty good. Unless you are running something else from the turbo back??

[bark]

To be honest I'm not sure of the dyno used and in what mode... However I can tell you the size of the dump is about 1.75" (same diamater as turbo exhaust outlet on the td05), then it goes into a 2.25" exhaust all the way. My theory at the time (which was probably wrong) was how could a turbo flow more exhaust gas than what comes out of the turbo exhaust?? Hence why I went with the same diameter - if that all makes sense?

I didn't get a trust dump or front pipe with my kit and had to get one made up. But I am considering re-doing the whole exhaust to maximise what I have.

[buz 138]

yeah good point. its only ever full power results you hear about.

i'll have to get under the thing again soon (good fun that is trying to make ramps for my ramps to get the low bugger up ) and actually measure the size i have now. i was told when i bought it it was 2.25 but cant recall it being that..

ok next question..does anyone make the dump pipes or is it a custom job? i think i'll still try and make it myself anyway. just mild steel ok for this?

[mx52nv]

Hey buz 138 and bark,

ok next question..does anyone make the dump pipes or is it a custom job? i think i'll still try and make it myself anyway. just mild steel ok for this?

I think Flyin' Miata do one for USD$220 plus shipping -> clicky.

I am pretty sure they fit but email them to confirm fitment with the Garrett/AVO T28 you have.

Alternatively, the SP one will also fit but no guarantee that Mazda will still be able to get one for you.

As for material, most stainless ones are prone to cracking which is why FM have used a cast one (same for the SP/SE).

However, whatever material you choose, please consider ceramic coating as a good method of reducing temperatures in the engine bay and increasing exhaust gas velocity. I have done this with great success to the manifold, turbo exhaust housing and dump pipe on Simon's 305rwhp SE and MX52NV (my old girl).

Let me know how you all go.
Les

[Sean]

Les is filling your head with good info

Like Les said, the AVO manifold are good for 300hp with the right supporting mods, the only real drawback of the AVO setup is the dump that he's already mentioned. To save you the messing around though, I can confrm the FM dumps will NOT fit with the AVO manifold, best is the custom made ones - A few places in sydney have made them for other MX5s running the AVO kits, or I'm sure Les could organise one and freight it too.

Back to your original post and the only thing I didn't like was the idea of running a link - I just dont like them, although i'm sure others love them.

Plenty of guys on here making good power with Autronic, Microtech and Megasquirts these days, from memory (i've been away from the forums for a while) a few of the NB crowd were now using Haltechs too.

[buz 138]

thats good to know they wont fit with AVO manifold. puts that idea out of my mind.

if i were to buy a ecu if would be the haltech i thnk...but the car came with the link so it will have to do for a while.

[Sean]

thats good to know they wont fit with AVO manifold. puts that idea out of my mind.

if i were to buy a ecu if would be the haltech i thnk...but the car came with the link so it will have to do for a while.

If using the link I'd be calling Flyin Miata, to get thier FMlink programming into it, changes the functionality out of sight - I think Gurglr used to run the FM modded link ecu, and it made good power back in teh early days, it was one of the benchmark turbo mx5s for quite a while.

[Juffa]

If using the link I'd be calling Flyin Miata, to get thier FMlink programming into it, changes the functionality out of sight - I think Gurglr used to run the FM modded link ecu, and it made good power back in teh early days, it was one of the benchmark turbo mx5s for quite a while.

Yep, that is a good option and is what I have on mine. The new chip was about USD$50. Takes 20 min to replace, including pulling back the carpet to access the ECU. One thing to note is that the FM ECU will give you way more functionality, but you need to buy some extra items, such as a air temprature sensor as the latest chip needs it to run http://www.flyinmiata.com/index.php?dep ... r=07-47100.
You also need to move some of the wiring around in the ECU wiring loom....but much cheaper than a new ECU and FM offer great support...and lets not forget the big support group on the big forum.

J

[wazman]

I just finished turboing my NB and used a modified HKS dump off a silvia. Also using custom manifold.



I think there is an greddy ex gate kit in the for sale section...... just buy that....... Good luck.