Why is my spool slow?
 

Hello everyone,

This is my first experience with turbo on a miata.:noob: I've fitted the Begi S3 kit on my standard 1,6 '91 115hp engine. In my opinion the engine spools rather slowly, or at least I want it to spool faster : ) I reach the max of 11 to 14psi (depends on the outside temp) at 4300rpm...

I would like to have full spool on at least 3500rpm if possible???

I've read some spool data and noticed that most of the cars do better than my setup at the moment.

This is my setup:
- Garrett GT2560 Turbo with Ball Bearings and Water Cooling, ceramic coated
- Stainless Steel Separated Gases Downpipe 2,5"
- IC # 2 rated to 300 whp
- ceramic coated standard manifold
- ms2pnp with EBC (no variable tps)
- OBX catback system with cat replacement (open) I think 2"or2,25" not sure
- the original begi recirculate valve (looks crappy)

If needed I will post my current MS2pnp mapping or anything else to help me solve the issue.

what could solve my problem? bigger exhaust, better mapping, smaller turbo,or anything else...

thanks everybody

you have a 1.6L with a shitty exhaust.


fix these issues.

3" exhaust should make a big difference. And variable tps with better tuning probably wouldnt hurt.

1.8 swap would make the biggest improvement.

What exhaust would you advise? Has to fit on my current Begi downpipe.

I added my msq file, maybe someone could analyse it? I prefer a save tune above a "max power with risks" tune. Yes, I'm a woosy



Thanks for the fast reply

Use EBC, as it will aid spool by quite a bit.

Yes, I agree. But I will stick to the 1,6 for now. Upgrading to 1,8 will cost a lot of money. I would like to solve my problem on my 1,6 as good as possible...

I do use EBC, but for the moment it's not programmed in closed loop because I am not able to do it myself (lack of knowledge:vash:)

I've read some posts about it but still it's not very clear to me.

I have to learn a lot about programming my MS2!!

You prefer a safe tune, but a safe tune will mean slower spool than an aggressive tune. More timing = more complete burn = more exhaust gasses = more spool.

I wouldn't assume the tune is your problem until you can test with a good exhaust (3" straight through).

FIRST check for obvious problems:

- wastegate flapper valve is sitting slightly cracked open
- leaks in intake plumbing.

:giggle:

:laugh:

What about just drive with the downpipe and delete the rst of the exhaust for spool test?

[/thread]

What's to test? We don't need to test 2" vs 3" exhaust, because 3" is better at every power level.

As a fellow 1.6 owner, I hate to say it, but if you want an improvement get a 1.8 w/ 3" exhaust. Or at least upgrade to 3" exhaust on the 1.6 and live with decent but not outstanding spool.

@FRT_Fun I agree, unfortunately you're right but I have to do with 1,6 for now...

@thenuge26 My idea was to remove the complete exhaust and test with only the downpipe fitted. Would this give the same results in spool as a 3" exhaust or am I completely wrong?

@JasonC SBB no leaks wastegate flapper complete closed

Can somebody check my mapping please???

which 3" exhaust brand would you guys prefer? Available in Europe if possible... Do I need a 3" downpipe too?

thanks

Most would probably recommend an enthuza 3" exhaust. And yes, the downpipe is probably the most important thing for you to fix right now. That thing is terrible.

Fireindc I think you are thinking of the other noob with spool problems, this guy has the Begi 2.5" sg dp, not that abortion from the other thread.

Going from a 2.5" dp to a 3" will still help though.

Sounds like you are in Europe, so shipping on an exhaust system would be quite expensive. I own and recommend Enthuza, but in this case I would either find a vendor in Europe or have an exhaust shop build one from scratch.

2.5" exhaust with a straight through muffler would be the setup I would go with. Not sure that 3" is really needed with a 1.6, but it wouldn't hurt either except for being more likely to drone.

3" vs 2.5" is still worth a significant improvement in spool at any power level.

If 3">2.5", then why not 3.5"? 4"? Maybe with a 6" exhaust it'll spool up at 500 RPM!!! Where's the diminishing returns?

Anyone have data showing an improvement on a 1.6 going from a 2.5 to a 3"? I cheked on my VVT motor and the difference was slight (<100 rpm).

I'll be the dissenting voice and say at his power level a good 2.5" exhaust will not spool noticeably worse than a 3".

After eliminating leaks in the intake piping and the 2.25" exhaust as the cause of slow spoolup the biggest improvement will come from a smaller turbo. The GT2554 is big enough to max out the torque capacity of the stock rods in a 1.6.

If the question was 'should I upgrade from my good 2.5" exhaust to a 3"' I would agree with you. But if OP is getting a new exhaust anyway, why not go for 3"?

And if a 3.5" downpipe would fit without major modification I would bet that everyone would would have 3.5" turbo back. Why not?

The muffler will likely be a big restriction if it isn't a straight through design that you can pass a golfball through.

Is the enthuza 2,5" or 3" very loud? I know it's louder than stock, but I mean too loud for road use? I like a sportive street sound, but not a very loud exhaust

2,5" vs 3" found this for what it's worth
"nahh you dont need 3 inch exhaust for power..." - MX-5 Miata Forum

I'm getting smarter, please feed me more guys :bowdown:

y8s ran a 3" exhaust and a 5x11x22 muffler and it was barely louder than stock.

I've never heard the enthuza exhausts, but the 3" FM exhaust is definitely a streetable noise level. You're not going to mistake it for stock, but it's quite reasonable.

--Ian

Enthuza is loud to me. YMMV.

So a 2,5" or 3" exhaust is a must, thats for sure now. Lets say that the spool will improve about aprox 300rpm compared with my 2" now? Right???

If I would mount forged rods an go to a safe 1,3bar=18,8psi would this improve my spooling?

More boost just takes longer to reach. You could turn it up to 18 psi today if you wanted, it would still reach 10 psi at the same rate it did yesterday.

ok thanks Braineack & thenuge26


more good exhaust system brands?

Other advise?

:sadwavey:

almost everyone gets them custom made or tailored. there isn't a lot of aftermarket companies we are aware of, especially outside the US, that make miata turbo specific exhausts

Agreed.

If you give Enthuza a call, you can customize the number and type of resonators and/or mufflers. I talked to the owner about my Miata build, sound/noise level requirements, etc and he built a header back exhaust to the agreed to specs. He was very helpful.

Doesn't help someone in Europe and lot, but thought a more local reader might find this a good option.

I asked jason to fit a 5x11x22 muffler for me; he refused so i did it myself.

I've sent Abe an e-mail. Those Artech pipes are absolutely beautiful...

I will order one from the USA if no other option...


the only 2,5" made in Europe I found was this: Simons:
Mazda MX5

It's a shame that magnaflow doesn't provide one. the only 2,5" they have is with two pipes. the single one is 2,25... Damn

And 3" is custom order USA, no other options. the question I keep asking myself is: Do I need a 3" exhaust after a 2,5" Begi DP for max 270rwhp (in the future)?

I have no idea what a shop near you would charge, but I imagine it would be less than getting an entire exhaust shipped from Artech. Is there anyone in your area that does custom exhaust work?

Nope, and if so totally unaffordable. In Europe it really sucks to buy parts for two reasons.
- to expensive
- mostly non existing

Everything I search for but can't find => Buy in the USA :party:

I bought wheels, turbo kit,clutch, stickers,gauges,spoilers and so on
The only thing that really sucks are the import taxes and customs (In Europe)
The rule for Europe (Belgium in my case) is quite simple: add 33% to the value of your order and that's the price it will cost :vash:

Right, but you can buy the big 5x11x22 magnaflow and have it shipped to you, then have Joes Exhaust Shop weld it up for you. That way you add 33% to $120 instead of $1200.

Most of the exhaust systems I saw, cost about $450 to $600...
$1200 what am I missing?

Where did you see that? Most cost $450-600 for the catback, and another $300 or more for the midpipe/cat.

Oh, I see, you have an NA. I'm looking at NB systems I guess, which are a lot more expensive. I never noticed since I've never cared about NA exhausts.

I've ordered a 2,5" cat replacer and cat back system. I know a 3" would be better, but a full 2,5" system is way better than what's installed now.
At the moment my decat pipe is 2" and cat back 2,25"

suggestions for a next step?

yes.

3"

Or 1.8 swap.

@18PSI

can you show me the difference in power gain on a 1,6 with a 2,5" vs a 3" please?


@leafy
1,8 swap is not an option for now

Has next to nothing to do with motor size. You have a turbo car, and you're making xxx amount of power.

If there's power gain on a turbo 1.8 going from 2.5" to 3.0" then there's gains on a turbo 1.6.

I don't need to show you anything. I don't care. You see - when we suggest things to people around here the burden of proof is not on us, because ultimately its your car and no one cares. We simply provide advice based on what we've experienced and seen. No one is going to go out of their way searching for threads and info...You should be the one doing it. You asked for advice on improving spool, you got it. You decided to do like 3/4's of it, then ask us "what is the next step". Its almost like you really want to spend more time and money for less results. Why not just do something properly from the get-go?

Just a thought.

Dirty vlad and the boys are right again. OP return your exhaust while you still can and get something you wont have to upgrade again down the road, it sucks, i know.

Ok, I give up ;) What about FM?

my only other option is return the 2,5" and buy this one
fits my 2,5" DP
http://www.flyinmiata.com/tech/dyno_...id_exhaust.pdf

Sure looks like a 3" exhaust.

waste of money?

I'm a little curious as to how you arrived at that conclusion...

Sorry, my mistake. My english is like my exhaust. Not very good at the moment. :rofl:

Now I know: sure looks like = is

Thanks concealer404

:makeout:

Now figure out a 3" downpipe or something for maximum baller.

:giggle:

Glad you are going for a 3" now. I too thought 2.5" "was enough", now i'm going to re-buy a downpipe and exhaust because of it.

By once, cry once.

It's all in the downpipe anyway.

Just do a 3" turbo back, and call it a day. This REALLY isnt complicated.

3" turbo back.

Mandrel bent.

High flow cat or none.

Straight through mufflers you can roll a tennis ball through.

Done. Honestly.

Dann

Regulation tennis ball is 2.575–2.700 inches

http://builder.cheezburger.com/Build...9-c146624acb76

Its a pretty common figure of speech when referring to mufflers.

Dann

I know, I'm just feeling snarky and I had to look up the tennis ball thing the other day so it was topical. ;)

I'm really not one to talk, I'll be running 2.5" from DP to bumper because I can't take good advice. :party:

Question: Who is the weenie complaining about slow spool? Answer: Not the guy with a 3 inch exhaust from the turbo back.