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Old 06-10-2007, 11:20 AM   #1
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Default HOW not to blow up your Engine Guide

Ok, with the recent batch of FUBAR'd engines, I think it's time for some suggestions and preventative procedures.

1. Buy a boost gauge. Stock greddy kits should not go past 5.5psi as the stock fuel pump can't supply enough fuel pressure.

2. Buy a wideband. A/f ratios are very important in turbo'd cars. This used to be an expensive mod, but with the LC-1, this can be had at minimal cost....can even be programmed to show a/f ratios on a narrowband gauge.

3. Stock 1.6 injectors can only safely supply enough fuel for 8psi.....this is at 100psi of fuel pressure which is the limit rating on your "15 year old" fuel lines coming off your fuel pump....so it's still borderline.

4. Engine knock is a bad thing. Even with proper a/f ratios, audible knock can be heard. Alot of the time, your engine can knock and you can't hear it. 90-93's have a real oil pressure guage, so you can look at this when you accelerate. It will bounce if your engine is knocking....even when you can't hear the knocking.....great tool for us audiophiles that like to listen to music in turbo'd cars. A basic rule of thumb on most 1.6's is 1 degree of retard per pound of boost. I found I needed to go more because of my shaved head. Always use the highest octane you can. I've heard audible knock with 91 octane, and been fine with 92 and up.

5. 15psi on a Greddy is different from 15psi on a different turbo.

6. Don't use the 12:1 vortech disk with your new Walbro, unless it's the GSS250 low pressure 190lph. 190HP or the 255 will be suicide.

7. Keeping tabs on your fuel pressure in a fuel pressure setup is a good thing. Fuel pressure will change with different weather changes.

8. Buy or build your own o2 clamp. Worth it's weight in gold. Lean tip in just before 4000rpm can create knock. O2 clamp will resolve this issue by tricking the OEM computer. Once knock starts, it takes twice as much timing retard to get it to stop. If there is no lean tip in, part throttle boosting is also a lot more enjoyable.


Well.....I know there are a ton more suggestions. Maybe you guys can add to this list. All I can think of right now. Happy "safe" boosting
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Old 06-10-2007, 11:45 AM   #2
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Dont listen to all the haters FMIC's are the devil buy WI
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Old 06-10-2007, 02:01 PM   #3
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9. For Greddy setups, Intercoolers are great just for the fact that it resolves the stock plumbing blowing off. But yes, after 5-6psi, some sort of IAT cooling is needed. If you go with only water injection, I would build a safeguard system with a solenoid safety that bypasses your MBC and a water level switch.....all this could probably be done for cheaper than an intercooler setup without the plumbing hassle, but you need to know your stuff with electronics.

10. If your not that good with tuning, you may want to invest in the J&S safeguard system. It will automatically retard your timing if knock is heard.

11. You should think of some sort of engine management after 8psi on a Greddy setup.

12. When tuning engine management, anything above 80% duty cycle is bad......learned this the hard way, but I was able to save my engine.

Last edited by MiataNuTca; 06-10-2007 at 10:56 PM.
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Old 06-10-2007, 02:39 PM   #4
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Duh, check and change your oil and coolant levels regularly should be #1
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Old 06-10-2007, 03:45 PM   #5
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I'm running a 190HP and a 12:1 disc...
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Old 06-10-2007, 03:58 PM   #6
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i was 2 and a 255 HP with a 12-1
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Old 06-10-2007, 04:17 PM   #7
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Take it slow and make sure you know what you are doing. Big boost = big power = big boom if you don't do it RIGHT.
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Old 06-10-2007, 06:28 PM   #8
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ummmmmm im running a 12:1 with my 195 lph hp
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Old 06-10-2007, 07:02 PM   #9
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Glad to see I'm not the only one.

What's "suicide" about it anyhow? @ 5psi (which I'm still running) 43 + (12x5=60) = 103psi fuel pressure. Unless I'm off on one of the variables??
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Old 06-10-2007, 07:09 PM   #10
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nothing just most people only via for 200 whp or so 103 psi is overkill for them unless they run IC's in wich case they need 10-1 fueling to keep from detonating j/k
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Old 06-10-2007, 09:14 PM   #11
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I thought for proper fueling 50psi +6psi per pound of boost for a fuel pressure setup. With a 12:1 your maxing out your HP pump. Your 15 year old lines are only rated for 100psi max....you guys are crazy. That and the higher the pressure on the rail, the more umph it takes for the injector needle to close.....high chance of injector lock.
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Old 06-10-2007, 09:29 PM   #12
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Quote:
Originally Posted by MiataNuTca View Post
I thought for proper fueling 50psi +6psi per pound of boost for a fuel pressure setup.
Not exactly. Look at the RC site.
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Old 06-10-2007, 09:39 PM   #13
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If the HP is rated for 130ish psi and I'm running at most 103 psi.. how is the pump maxed out?

I'll just keep it like it is until I get back and throw in the MS and 460s.
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Old 06-10-2007, 10:50 PM   #14
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Quote:
Originally Posted by MiataNuTca View Post
If you go with only water injection, I would build a safeguard system with a solenoid safety that bypasses your MBC and a water level switch.....
It's not completely foolproof, but then I'm only a partial fool. Feel free to copy / improve:

https://www.miataturbo.net/forums/showthread.php?t=9083
https://www.miataturbo.net/forums/showthread.php?t=9256
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Old 06-10-2007, 10:55 PM   #15
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Quote:
Originally Posted by kotomile View Post
If the HP is rated for 130ish psi and I'm running at most 103 psi.. how is the pump maxed out?

I'll just keep it like it is until I get back and throw in the MS and 460s.
What are you measuring your fuel pressure with?

If your running a fuel pump capable of that pressure, using the 12:1 disk is going to max out the pump at 7psi (130psi) and it would be over 100psi at 5+psi of boost. It's only a matter of time until you will see a hydrolocked injecter.

Last edited by MiataNuTca; 06-10-2007 at 11:15 PM.
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Old 06-11-2007, 01:31 AM   #16
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Quote:
5. 15psi on a Greddy is different from 15psi on a different turbo.
And? Just like 15psi on any turbo is not the same as 15psi on a different turbo. I really don't know what you point is.
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Old 06-11-2007, 03:52 AM   #17
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And? Just like 15psi on any turbo is not the same as 15psi on a different turbo. I really don't know what you point is.
Each turbo has different flow (CFM)....it's common regard (least on Mnet) to say the 90-97's can handle 15psi of boost before they grenade, I was just stating that 15psi is too general of a term to decide if that's the limit. Hopefully by those higher boost numbers your educated enough to know the difference between flow and pressure.
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Old 06-11-2007, 09:53 AM   #18
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Quote:
Originally Posted by MiataNuTca View Post
What are you measuring your fuel pressure with?

If your running a fuel pump capable of that pressure, using the 12:1 disk is going to max out the pump at 7psi (130psi) and it would be over 100psi at 5+psi of boost. It's only a matter of time until you will see a hydrolocked injecter.
Where did I say I was running 7 psi?

I'm not measuring fuel pressure with anything other than math :gay: see equation in above post.
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Old 06-11-2007, 11:18 AM   #19
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Quote:
Originally Posted by MiataNuTca View Post
Each turbo has different flow (CFM)....it's common regard (least on Mnet) to say the 90-97's can handle 15psi of boost before they grenade, I was just stating that 15psi is too general of a term to decide if that's the limit. Hopefully by those higher boost numbers your educated enough to know the difference between flow and pressure.
Ya I got that. I just didn't know why you specified the TD04H-15G. It reads like the Greddy turbo is some really strange animal.
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Old 06-11-2007, 12:25 PM   #20
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ummmmm so are you saying im gunna burst my fuel lines because im running 1.8 injectors 195lph hp pump and a 12:1 disk?????
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