Discussion in 'Mazdaspeed 3 Build Diaries' started by Sho, Feb 10, 2016.
Agreed, winter has already gone on too long. I've got people to do, mods to put on, logs to make...
Haha winter just started, i feel you. Too bad the cs tb wont work with the fost mani. Ive been looking at an aftermarket fost mani to make use of that bigger tb. I emailed breedt today asking dimensions.
@Speed Solutions LLC is supposed to be making an adapter plate for the st mani and Cs tb. Hit him up
Thats nice but the inlet is only 67mm i think so it would give you a little. A new mani would be optimal. Im still scared im going to split the seam on the mani at 35psi. Good thing i havent redone my coldpipe yet so i can think about this.
Cant wait to see how that TB does. You plan to slap it on and see or wait for mani as well and do both together? Your car is so choked the TB alone may be significant .
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It'll likely go on as a combo with the manifold once I can find one and then get retuned (touched up). It's too cold right now to pull the speed out of the garage and drive it on the r888's. We'll see though
Throttle body shipped today!
On another note, 7 emails from CS in an hour and a half for one purchase is kind of... Unnecessary.... LOL!
So, since it was randomly in the 60's today, I decided to work on the speed a little and take it out for a drive.
First, replaced the original 232k mile driver LCA. The passenger will get replaced next time it's warm out.
Then, swapped the stock TB for the CS TB
My initial thoughts:
First off, keep in mind I have a full 3" diameter cold side from the outlet of the tr1235 all the way to the TB, so with the stock TB, drivability was always kinda poop with low throttle input below 2500rpm. And I'm currently on a stock manifold that is ported (soon to be upgraded)
1. Low throttle response is now much smoother at low rpm. It takes very little input on the pedal to get a response. Much better vs stock TBwith the 3" cold side.
2. When letting off the throttle and engine braking, it's very rough. In any gear, whether at city speeds or highway speeds, once the TB closes, the car jerks. Stock TB didn't do this. Not sure if this is something that can be tuned around
3. RPM hangs at 1500+rpm when going into neutral and coming to a stop and hang there once stopped for a half second or so. Not really an issue, but I know my stock TB would hang around 1100rpm going into neutral and drop down to idle rpm when the car was below 5mph. Again, might be able to adjust this once retuned.
4. Install was easy, not having to dick around with a gasket was nice.
5. Included couplers and t-bolt were nice quality.
More to thoughts to come once it's not Ohio winter and I can WOT. Not sure if I'll have a different intake manifold by then or not. But I'll review further, down the road.
Yeah since I have never bothered to throw my winter tires on I hadn't driven the speed in 5-6 weeks. It was so nice to be able to go out with it for a day. Damn I want winter to be over.
Hmm, interesting on the TB. Keep us updated on it. Your thoughts maybe what push me to get one or not
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I've driven a lot of stock TB cars with this problem. It is more common than you realize. I don't know whether you can tune around it electronically by playing with the throttle mapping, but the fact that CS doesn't include such instructions leads me to believe it either isn't possible or necessary. You will, however, find changing your bypass valve or bypass valve springs can have a significant effect on this. One of the main reasons I use a basic push-type bypass valve (I have the original Corksport one) on my car is because it drives much more smoothly during part-throttle transitions than other valves. I would suggest using a lighter spring in your bypass valve.
What you are feeling is a failure of the bypass valve to open quickly enough, and it's no surprise when you think about it that this would cause the problem you describe. The reason this problem has started now is that at the same "fully closed/parked" throttle position (I am assuming your throttle mapping is the same), your intake manifold will now see less vacuum with the larger throttle body, due to maths. Less vacuum acting on the backside of the valve will cause it to open more slowly.
Interesting. I'm running a tial Q (no recirc) and it's on my hot side piping.
My tuna had this to say about it :
"The decel is the big problem with the bigger TB’s. It’s even worse with the old school 75mm TB I used to run. The problem is in the dfco tables for the most part. Basically, fuel cuts too rapidly because it’s using the stock values.
Problem is Cobb no show these tables, only versa and Mazda edit."
I see what he means. I just opened VT and I see the tables he is referring to. That could possibly work. Try the bypass valve spring though for real. I saw what bypass valve you are using in your signature. That is why I recommended trying a different spring. Did you ever try using a lighter one? Did you have flutter issues?
No flutter issues. I get a clean blow off in both high and low boost situations, which kinda makes me weary to fuck with it lol. I'll have to see if I even have the other springs laying around as well.
If you didn't have any flutter issues with the lighter spring then I don't understand why you're using a heavier spring. All that will do is make drivability worse at part throttle conditions.
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I never changed the springs in it to begin with lol. Bought it second hand, and just cleaned it and lubed it before install. I'll look and see if I still have the springs and if I do, I'll try a lighter one
My apologies. I obviously was not clear in my post. I was asking if you'd experienced flutter with a lighter spring. I am surprised you never messed with the springs before. I actually researched using a lighter spring in my Corksport valve soon after I bought it because I recognized that it didn't operate as smoothly under certain part throttle conditions compared to the OEM. Unfortunately I found the wave spring isn't really available in a wide range of options. It still drives really well anyway compared to most valves of course. But your Tial valve comes with a range of springs to help tune the kind of behavior we're talking about here which is nice and part of the reason it's more costly than other valve options. So I'd encourage experimenting with the springs. If nothing else you can confirm your current configuration is the best compromise.
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Do you have any logs of before and after the throttle body logging app and tps and some 4th gear pulls to see any difference in turbo response? I know its winter but i needs to know if its worth my monies. Do you know if your tuna has tried dumbing the throttle down a little in the app translation and dbw tables? Ive had a lot of luck playing with the tables for first and second gear to help out with drivability of the act ceramic 6 puck.
No logs yet. Back to snowing and cold here, so car is back hiding in the garage. It's supposed to be 50 on Sunday, though. So if it's dry out, I'll try to grab a log for comparison.
No adjustment for the tune yet, either as I'll wait till I have my jmf installed before returning.
As far as throttle tables, my 1st and 2nd gear are neutered quite good via dbw tables and load to keep me at 9psi peak in 1st gear, 12psi in 2nd, then 35-36 peak in 3rd, 4th,5th.
Yea i imagine having fwd presents a lot of problems with your turbo. Ill bet those throttle table adjustments make a huge difference in city driving. How does it feel with your clutch tho. I had to sharpen up my throttle tables and make the throttle response a little snappier, even with a lighter single mass, to get the studder after low speed/rpm shifting to go away. It also made rev matching downshifts much smoother. I love ceramic clutches break-in but the kevlar clutch was buttery smooth, just like stock.
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