Thinking about going V8, what are my parts worth? - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 01-04-2008, 10:13 AM   #21
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Originally Posted by Arkmage View Post
yeah, but with 3 PcPros you are dumping in so much intercooler... I mean fuel... that you might as well have a v8... you'd get better fuel economy.
lolololol
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Old 01-04-2008, 10:14 AM   #22
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It isn't unsuitable, I just am unhappy with the current results. The car drives ok, but just doesn't sound good. I feel like I have to kick it in the butt to get it to do anything and that isn't what I wanted the turbo to feel like. I know there is probably something wrong with the install right now because the turbo doesn't reach full boost until almost redline and something isn't preventing the kit from massive boost creep at the high end. I took a friend out today and the Hydra was cutting fuel around 6k rpm. This means I was getting 14psi instead of the 12 I want. ARGH!! I don't want to grenade my engine, but I am a logical guy and I can't seem to find a primer on "if your data log looks like _this_, adjust _this_ to fix it". I understand the principle of a boosted engine, I just am not fully sure how to get the Hydra to do what I want.

This was just a feeler to get an estimate of how much more it was going to cost me to get something stable and consistent. Quality features in a daily driver
Ok this is precisely what I thought was going on. I think that you need to get the car sorted and keep your head cool a little longer. Really you should be able to have a car that feels every bit as strong as a V8 (although at slightly higher RPM's.) It's not unreasonable to expect 240+ ft/lbs of torque and 240 RWHP from 4000-7000 RPM with consistent boost.

Since you have an FM kit, hold their feet to the fire and get them to help you troubleshoot the car. They are normally pretty helpful, even if some of the staff there can be annoying, still they know the system and have seen all these problems before.

I fear a V8 swap may not be the solution that you are really looking for.

Mark
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Old 01-04-2008, 10:18 AM   #23
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It isn't unsuitable, I just am unhappy with the current results. The car drives ok, but just doesn't sound good. I feel like I have to kick it in the butt to get it to do anything and that isn't what I wanted the turbo to feel like. I know there is probably something wrong with the install right now because the turbo doesn't reach full boost until almost redline and something isn't preventing the kit from massive boost creep at the high end. I took a friend out today and the Hydra was cutting fuel around 6k rpm. This means I was getting 14psi instead of the 12 I want. ARGH!! I don't want to grenade my engine, but I am a logical guy and I can't seem to find a primer on "if your data log looks like _this_, adjust _this_ to fix it". I understand the principle of a boosted engine, I just am not fully sure how to get the Hydra to do what I want.

This was just a feeler to get an estimate of how much more it was going to cost me to get something stable and consistent. Quality features in a daily driver
You belong on this forum. You've got to be kidding. You're going to sell a 250whp miata and stuff a 200+lb v8 in the car because you don't like the way it sounds?

Everyone talks about how FM will shoot a load in your mouth if you buy **** from them, so why don't you call them up, ask them questions about their "superior to MS (because it uses all the factory sensors)" engine management and maybe you'll get bukkake'd.

Lets see...you're overboosting...I wonder what you can do? Obviously you need to sell the car because no one has ever fixed over boost, or experienced it and lived.
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Old 01-04-2008, 02:39 PM   #24
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Ok ok, thanks for the level headed feedback guys. I am going out of town on business for a month so I will have some time to figure out what I need to do to fix this problem. As I said before, I was just 'thinking' about it. Of course, when I told my wife I was thinking about it, that is when she finally authorized the turbo kit. You are right though, I am probably jumping the gun a bit and should just focus on getting this fixed.
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Old 01-04-2008, 04:53 PM   #25
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so I got a damn flat in my miata today. I burned the car and left it on the side of the road.
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Old 01-04-2008, 05:52 PM   #26
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how did you burn it...po pro died on ya?
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Old 01-04-2008, 06:39 PM   #27
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so I got a damn flat in my miata today. I burned the car and left it on the side of the road.
Hrm... I get the hint I am being made fun of here...
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Old 01-04-2008, 06:44 PM   #28
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Ok ok, thanks for the level headed feedback guys. I am going out of town on business for a month so I will have some time to figure out what I need to do to fix this problem. As I said before, I was just 'thinking' about it. Of course, when I told my wife I was thinking about it, that is when she finally authorized the turbo kit. You are right though, I am probably jumping the gun a bit and should just focus on getting this fixed.
I think you will find debugging your current setup will be much more time and cost affective than a v8. I personally would like a v8 as well, but I love the turbo and won't change this car. If anything I'll get a v8 in addition to this one.

The fact that you aren't making boost until high up in the range suggests that you have one of the following problems:

1) A boost leak. One of your intake pipes is probably leaking. Easy way to find the leak is to put a PVC cap into the ends of your piping at the turbo and TB. In one of these caps thread in an air line fitting and hook up a regulated air supply @ approximately the level of boost you run. If there is no leak, inspect the two couplers at the turbo and TB ends, and call it good. This is probably the number 1 cause of low/late boost.

2) WG is failing open. This is usually caused by improper arm tension or a worn/weak spring. If you can open the wastegate by hand without significant difficulty while the actuator and arm are attached then this is most likely the culprit. Retension the arm much tighter and/or replace the actuator.

Your overboost problem is likely caused by:
1) Inadequate downpipe flow from the wastegate port. This can be solved by enlarging/smoothing the tubing from the wastegate exit to the rest of the downpipe.

2) Electronic boost control not tuned properly (if it's electronic)

3) Faulty wastegate actuator. This can be tested by hooking up regulated air to the actuator and creeping the pressure up. determine what pressure (if any) causes the wastegate to fully open and go from there.

My guess would be that you are experiencing a combination of boost leak and wastegate failing closed. Once the airflow from the turbo exceeds that of the leak in the plumbing your boost shoots up. Either the wastegate is not responding fast enough or is not responding at all.
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Old 01-04-2008, 07:06 PM   #29
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I agree with you, but I don't think I have a boost leak right now. Here are two of my data logs. My feeling is the most likely culprit is #3 but the replacement FM sent me did the same thing. Maybe I should take Stephanie up on her offer and get the BEGi unit to see if that improves the situation. These logs don't show the boost creep problem. I am going to do some more runs tonight and show you what the car is currently doing. Maybe I should close this thread and make a new one for diagnosing the problem...


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