GT2554 spool is horrible
 

I've got a 96 with a BEGI log manifold, GT2554, BEGI seperate downpipe, hollow stock cat and 2.25" racing beat exhaust. The spool seems a lot shittier than it should be...

with the actuator arm tightened all the way:

5psi at 2600rpm
10psi at 3400rpm
15psi at 3800rpm

i dont have a preturbo leak, actuator arm is not opening prematurely. This can't be normal right?

isnt the 2554 one of the fastest spooling turbo's out there? When people talk about them, its usually the turbo with "no lag, instant power, etc"......so ya, Im going to say something is wrong.....

You're trying to achieve 15PSI on the stock wastegate can alone, and complaining about how long it takes?







.

Joe, EBC is hooked up at 100% DC throughout the table. i've also tried it with the actuator can pressure line completely unconnected so it never sees any pressure. This is the fastest it will spool, should i be using a different can?

regardless of whether the actuator line gets pressure or not the can you are using may be too weak to hold the flapper door from blowing open. I thought I had a boost leak on my begi/2554 but turned out to be that. tested by locked in arm in place with a pair of vicegrips and then being very careful going for a test drive. boost was instant so i knew that was the problem. i tightened the actuator arm all the way down and that made a huge improvement. yours may be a lil weaker than mine.

i think the flapper door blowing open so easily might have something to do with BEGi porting the turbos. we need more flow out the wastegate to eliminate boost creep so that's what we get. if you want to have your cake and eat it too it may be necessary to go to a stronger actuator.

were you expecting 15psi at 2600RPM.....that's undrivable. I don't see the issue. 15psi around 3800rpm sounds about right with an exhaust that's not designed to flow good.

i see 7ish psi @ 3k rpm.....so i am on par with you (i have no boost controller).

I see 10psi at 3000 rpm on my T25.

I think his exhaust is the culprit.

Stock hollow cat and 2.25" exhaust, chaaaa ching motherfurcker!!!!
You probably gutted the stock cat yourself didn't you? This causes a massive restriction unless you honed the damn thing. Get a test pipe in there and you should see half of your problem go away. Get a real exhaust from Jason and do what Paul says in regards to the WG actuator, I don't know this from experience but he has never steered anyone wrong.

simple test:
1. set overboost cut to 15 psi
2. remove vacuum line from wastegate actuator and plug vac line.
3. log that bish.

Paul, when you say instant, you make 12psi by what rpm? i have the arm tightened down all the way and you need a gorilla to get it to move, but i'll check again with the vice grip trick.

YS8, this is what i did to get the spool numbers i listed above.


Can my 2.25" exhaust really be the culprit by that much, or am i just expecting too much by all this "instant boost" talk?

plus the gutted stock cat....most definitely.

Think about it, on my ancient t25 I get boost onset by 2500rpm by 3000 I get 10psi flat to redline on a begi S downpipe and a enthuza catback(stock cat in place).

How fast JasonC SSB spools in PSI on a 2254 and a AVO and BEGi manifold:


like i said, sounds like you are on par....


but just to piss you off, with my T3, I see:

Jason's pulls were done in 2nd gear, mine is in 4th. There is a drastic difference in spool between 2nd and 4th.

ah yes, should be faster in 4th...mine were third :)

Way to rub it in... Mine hasn't been chewing screws though :fawk:

was just looking over my datalogs from our last dyno day in may...

I think I'm gonna have to go log a 4th gear pull in both the Machine and DD and post the results. Just gotta talk the girlfriend into it now. BRB.

Well I got the approval from the GF but only took the Machine out. Takes me 20 mins to get to a highway where I can do this sort of shit in that car.

Anyway here is how fast Paul spools with his 2560. It's about 80F out when I did this. 4th gear.

100% tp @ 1850rpm

2000rpm 2.0psi
2200rpm 4.0
2500rpm 5.0
2700rpm 6.5
3000rpm 10.4
3200rpm 14.0
3500rpm 14.2
**********Obviously from here on up and can put the boost where ever i want it. i want it at 14. Boost duty cycle at 3300rpm is 61 and goes lower from there out to redline to maintain 14.

I think I need to look into an adjustable wastegate actuator or just a stronger one.

Thanks for the update Paul, good spool with that 2560! I wish you could post a log with your DD for a better comparison!

i'll try tomorrow. i'm actually letting it sit though since the front pads are so low one started grinding. new are on order.

NO FEAR: If you aren't living on the edge, you aren't living....

'94 1.8 (8.8:1 comp), GT2554R w/ 7psi can, Bell S3 manifold, SSSG DP, 3" metal core cat, 3" Enthuza

the equivalent of a 4th gear pull on a 5speed/4.1 car (5th gear in my car).

1750rpm: 1.0psi
1870rpm: 2.1psi
2014rpm: 3.3psi
2478rpm: 5.4psi
2626rpm: 6.1psi
2783rpm: 7.3psi
3004rpm: 9.4psi
3188rpm: 11.0psi
3394rpm: 12.5psi
3601rpm: 14.1psi

absurd.

I need real boost control instead of this ball 'n spring.

you like?

here's what happened when i pulled from 1750rpm

100% tp @ 1750rpm

2000rpm 2.9psi
2200rpm 4.6psi
2500rpm 6.5psi
2700rpm 8.5psi
3000rpm 11.6psi
3200rpm 14.0psi

Damn. damn damn.

I will datalog my car for sure, but I think the twins can't get to 14psi til after 4000. They make like 5psi really low but then sorta stay there until the revs climb.

Anyone want a TT setup? Maybe Mark will buy one of the 1548's. Partial trade for a VVT head?

I'll use the stainless absurdflow manifold that I'm making and the 2560 off my subaru. :) I bet artie is getting anxious.

Is It Done????

Sorry buddy, next week. It's close though.

ok so mine was from 2300. dyno operator gave me the "hammer down" at that point :dunno:

It's cool. Perfection needs time. Once its done I can dyno and post my spool numbers here too. Sorry for the thread hijack.

Man, I guess I need to ditch my RB exhaust as well. The T3 spools a tad late, anything quicker would be nice.

I performed some mild headwork and I gained a touch better spool.....this was with a 2.25" borla exhaust.

http://www.boostedmiata.com/log/headwork_boost.jpg

this is no headwork with a MBC compared to headwork with an open wastegate line.... what can clearly tell is the headwork helped spool the turbo a touch earlier....you can also see my boost creep started to appear :)


upgraded to a 3" magnaflow....the difference is clear:

http://www.boostedmiata.com/logs/hea...comparison.jpg

I'm seeing 14psi just before 4000rpm in 4th gear. I suspect I'll get a boost a couple 100rpm sooner when I change out my exhaust. right now it is 2 1/4" Spec Miata exhaust with an extra glass pack resonator. Ideal it's not. No fancy EBC, just a ball and spring MBC.

Cough cough....

there was mild work performed on my head....


happy?

Just stealing your lime light :P

How about this for an interesting comparison? My setup vs paul vs brian vs Sav

I just found my log here that I took about 2 weeks ago just to record my spool....

RPM PSI

2500 1.5psi
2700 3psi
3000 5psi
3300 7psi
3600 10psi
3767 11.6psi
3788 12.9psi
3861 14.0psi
3900 16.2psi

3rd gear, 70*F morning

in fourth, log shows spool is about 150rpm faster.

can you redo with those numberz please.

and add mine :D

here we go:

here we go

i tried to find a picture of the S3 manifold to compare Savington's to the rest but I gave up on the page when it tried to load 5 megs of thumbnails.

mo, if anything, add some timing between 1500 and 30ooRPM and 100-150kpa

curious, what does your timing map look like?

This was also a suggestion made by Corky, This is what i'm using Scott, let me know your opinion...

Why the fuck do i get the pink line?

Cause you're a ------, alright?

if you look at FMs default map for a 1.6L turbo, you can see what I mean. This is the area I wanted to play with last weekend on the dyno....

http://www.boostedmiata.com/timing/fmtiming.jpg

So i went and made changes to my timing map. see the before and after below and then look at the before and after spool improvement. In summary, nothing... any thoughts or theories?

get an ebc.....

if my test above (he says he did that) doesn't spool it any faster, an EBC wont do it either.

true...do that test.

I think the only thing to fix is this:

I have a similar exhaust and similar spool numbers. OP has an EBC already.

but you also have a smaller engine.

I think the exhaust is enough of a restriction. You'll probably see a larger gain than I will from a good exhaust setup.

Sorry I'm late to this party. I'm running the SR20det T25, BegiSS dg downpipe, 2.5" test pipe, 2.25" Borlas. My spool looks exactly like yours comp.

here's how sam's looks, compared to mine.

http://www.boostedmiata.com/dynos/sc...with_boost.jpg

The spoolup data in the above compilation is a 2nd gear pull. Here's the data with my 4th gear data added/

Great thread! Here is another one to add. I just hooked up my EBC today and am still tuning it so there is some overshoot and oscillation. The target boost is about 7.5 psi. This is a 4th gear pull on a hot 102 deg F day.

Setup
GT2560
BEGI cast manifold
BEGI stainless DP
2.5" exhaust: hi-flow metallic cat, straight through resonator, straight through muffler, all magnaflow
MS open loop boost control
GM boost solenoid
RPM Boost (psi)
2136 0.44
2378 3.53
2521 4.56
2864 6.91
3091 8.53
3184 9.11
3445 7.2
3694 8.09
3989 7.35
4294 7.64
4472 8.09

Here is a chart. Paul's spool is, well, absurd. Sav's looks great. Looks like mine is pretty good. I need to get that new clutch in so I can turn up the boost. The stock clutch is slipping fo sho.