Miata Turbo Forum - Boost cars, acquire cats.

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-   Dynos and timesheets (https://www.miataturbo.net/dynos-timesheets-21/)
-   -   1999 Forged Bottom FM2 w/ MS1 (https://www.miataturbo.net/dynos-timesheets-21/1999-forged-bottom-fm2-w-ms1-59859/)

shlammed 08-19-2011 02:33 PM

Gutted cat is killing you too. Unless you have a peice of pipe in it to smooth the innards out.

It probably had more flow prior to you gutting it actually.

Change that system to a sanitary 3" tube (polished inside as well as out) and profit 20whp over the entire RPM range. the cheated bends and short radius is hurting, the 2.5" it hurting, the cheated bends really hurt, the gutted cat is killing you. sorry, but this is why your dissapointed in your numbers.

Savington 08-19-2011 03:24 PM

With that exhaust setup, 225whp at 13psi isn't too far off. You have something funky going on at 6k+, let's see the timing map and datalogs. I bet you're crossing from the 183 cells into the 212 cells and the 212 cells are way retarded across the board.

18psi 08-19-2011 03:26 PM

Doesn't look bad to me either considering the setup

pdexta 08-19-2011 03:50 PM

If the car held topend like it should those dyno numbers are going to be ~245hp/231tq and it's right where you would expect it to be. I doubt that is going to be seriously affected by the current exhaust. I'm curious to see that timing map.

PS- More boost.

chokeasphyxia 08-19-2011 04:56 PM

6 Attachment(s)
Here's msq and log and fuel/spark maps.

Braineack 08-19-2011 05:07 PM

was your timing latency tuned? oh wait... MS1.... nothing control VICS either?

Savington 08-19-2011 05:32 PM



If any of you had actually tuned a car using vics, you'd understand that it makes no difference above 5500rpm. Cute, though.

Two problems here:
-flat timing to redline. The maps on my 2554r rose from 13-14deg at tq. Peak to 20+ degrees at redline. Turn up the timing past peak torque.
-fuel rises at 6500rpm at 212kpa. By like 5%. Ridiculous. With power falling, you need less fuel at high rpm, not more. All the T25 cars I've touched get less fuel at 7k then they do at 6k.

Add 2deg of timing above 5500, 3deg above 6200. Then fix fueling, I bet it's like 10.5:1 at 6500+. Those two are worth like 15+whp.

Braineack 08-19-2011 05:52 PM

why I asked about timing latency is the drop of timing at high rpms with MS1.

Joe Perez 08-19-2011 06:10 PM

1 Attachment(s)
MS1 has an adjustment for trigger latency just like the rest of 'em. It's under "Advanced Code Options"

https://www.miataturbo.net/attachmen...ine=1313791819

chokeasphyxia 08-19-2011 06:40 PM


Originally Posted by Savington (Post 761530)

If any of you had actually tuned a car using vics, you'd understand that it makes no difference above 5500rpm. Cute, though.

Two problems here:
-flat timing to redline. The maps on my 2554r rose from 13-14deg at tq. Peak to 20+ degrees at redline. Turn up the timing past peak torque.
-fuel rises at 6500rpm at 212kpa. By like 5%. Ridiculous. With power falling, you need less fuel at high rpm, not more. All the T25 cars I've touched get less fuel at 7k then they do at 6k.

Add 2deg of timing above 5500, 3deg above 6200. Then fix fueling, I bet it's like 10.5:1 at 6500+. Those two are worth like 15+whp.

+2 degrees of timing above 5500 across the whole board, or just the boosted cells (like 100+ kpa)? This is all new to me, thanks for the input.

Savington 08-20-2011 01:54 AM



I'd start in boost. You need to have a close ear on things. I was able to find det under 6200 in my 2554r car, with the same turbine and a bigger compressor you may find it a little earlier than I did. The fueling in general looks rough up top - some rows it drops, some it climbs.

Search for my 217whp chart, the timing map should be posted. Don't copy/paste, please, but do use it as a template for how the curves should swing up as rpm climbs and torque falls.

hustler 08-20-2011 02:21 AM

4 Attachment(s)
Look at the 3d view for both tables and tell me you don't think it's a disaster. Compare the shapes of your tables to the shapes of mine. I hope you didn't pay anyone for this tune. If you did, post his contact information.

After reviewing the log it's clear that fuel is the main problem, you're all over the place. Our engines seem to like 11.5:1 for torque, fix your fuel table then address spark next time you get on the dyno. Low compression engines need spark angle to come alive.

Savington 08-20-2011 05:53 AM

Now that I'm off my phone I can actually view the log you posted. No offense, but the fuel map is a total clusterfuck. Don't touch the timing until you get the fuel totally sorted out. California pump gas makes me more conservative than everyone else on timing, but 18 degrees on a 2560 at 14+psi sounds pretty aggressive to me as well. I would consider taking some timing out and work on the fuel map. You should be able to get the fuel totally dialed on the street, then spend an hour on the dyno finding det and/or MBT at various RPMs.

Braineack 08-29-2011 01:07 PM


Originally Posted by Savington (Post 761530)
If any of you had actually tuned a car using vics, you'd understand that it makes no difference above 5500rpm. Cute, though.

If VICs was kept on past the 5200RPM crossover point, the torque would drop off signicantly as opposed to when turned off. wouldnt it?


which could explain the nice bump in torque in the 4K range and the sudden drop after 6K.

chokeasphyxia 08-31-2011 09:25 AM

2 Attachment(s)
VICS actuator/valves are completely removed from my intake manifold.

On a side note, I've got a whole new IC/piping setup sitting at my house and a GT2871 will be here Friday.

https://www.miataturbo.net/attachmen...1&d=1314797123

Braineack 08-31-2011 09:46 AM

okay, then nevermind... pretty sure if the butterflies are kept closed past 6K the tq drops off like crazy.

but it appears with boost it doesn't effect it: https://www.miataturbo.net/showpost....6&postcount=14

pdexta 09-01-2011 11:53 AM

I saw this on another forum and thought I'd throw this out there since you're semi-local and there aren't too many dyno days this time of year. Apparently they're just putting it together, I'm sure more info will be available soon...


J&J Performance is holding a shop meet and dyno day on the 24th of this month. $35 for two dyno pulls with no AFR.

From 4:00pm-10:00pm.
http://jnjperformance.com/default.aspx

Braineack 09-26-2011 03:57 PM


Originally Posted by Joe Perez (Post 761546)
MS1 has an adjustment for trigger latency just like the rest of 'em. It's under "Advanced Code Options"

https://www.miataturbo.net/attachmen...ine=1313791819


mind blown. i did not know this.

Enginerd 09-29-2011 09:58 PM


Originally Posted by Savington (Post 761530)
-fuel rises at 6500rpm at 212kpa. By like 5%. Ridiculous. With power falling, you need less fuel at high rpm, not more. All the T25 cars I've touched get less fuel at 7k then they do at 6k.

Thanks for posting this. My fuel autotuning consistently pulls fuel after 6000rpm, and you are the first person to confirm my suspicion that it was due to the torque dropoff (supercharged) at those levels.


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