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

Dont listen to all the haters FMIC's are the devil buy WI

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.

Duh, check and change your oil and coolant levels regularly should be #1

I'm running a 190HP and a 12:1 disc...

i was 2 and a 255 HP with a 12-1

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.

ummmmmm im running a 12:1 with my 195 lph hp

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??

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

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.

Not exactly. Look at the RC site.

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.

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

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.

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.

Where did I say I was running 7 psi? :confused:

I'm not measuring fuel pressure with anything other than math :gay: see equation in above post.

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.

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?????

Maybe burst your old return line (after the 12:1 clamping) or hydrolock your injector. Are you running any sort of fuel management? You must be running big time rich!


12:1 means 12 psi of fuel per pound of boost. The vortech doesn't always run exactly at this ratio, but it will still be over fueling your setup with an aftermarket HP pump. Buy the 6:1 or get a Begi AFPR, or better yet, go standalone.

not if we shovel alot of air into it ive done it for a while ut works fine

So a Greddy running 12PSI would be how many on another turbo?

I am makin closer to 250 whp at 12 psi considerig my turbo flows 500+ cfm from 10 psi on ward and the td04 flows 428 cfm max think about it less abietic heat and more power. Alot of greddys at 15 psi can barely get past 270 whp for comparison.

Is that supposed to be a bad thing?

Unless your running low boost (5-6 psi or less), using a high ratio disc in the vortech will have your fuel pressure pegging out at 130-140 psi. I tested it myself with my FP gauge. With the 190HP fuel pumps, the best disc is generally the 4:1 or 6:1.

I ran it with an 8:1 disc and it was pegging 130 psi all the time. Car was bogging big time at high boost.

Sorry to hijack, back on topic.

No one is knocking the greddy turbo, it is capable of decent power. What people are saying is that PSI does not equal the same power output from turbo to turbo. 15psi on the greddy can equal 275hp depending on mods and tuning. Whereas a larger or more efficient turbo could reach 275hp at 10 psi. It's not how many PSI you run it's how much CFM you are running through any specific turbo. The greddy is only efficient up to 15 i believe, after that it is past its compressor efficiency.

Oh thought of another addition to the list:

change coolant hoses at least every 5 years and get some worm screw clamps on em. (for nestor)

But PSI doesnt vary from turbo to turbo, correct? I understand that the power output on one turbo at 15 psi is different then another. Your not saying that when my Greddy is putting out 12 PSI its actually 10 on another turbo. Isnt the stock motor only good for 12 anyway?

Another tip: T-clamps > Screw clamps

Didn't you just say that you understood that different turbos at different boost levels would be producing different power levels? That said, there isn't a magic boost level at which the motor dies.

On a 1.6? Without cams, N2O, or revving to 9000?

:inout:

Actually, the info on the 3KGT board, with compressor maps, says 24psi is max efficiency, with 28psi being max boost.

It's pretty simple. A larger turbo will push MORE AIR in the same amount of time as a smaller one at the same PSI. It isn't compression, it's VOLUME that changes.

Key word was could in that sentence, no one said anything about what motor, mods or redline. Given as general information of what could maybe be possible, not what is going to happen but i guarantee a big enough turbo at 10 psi would produce 275 hp.

That's a very misleading statement. A greddy turbo could possibly make 300 at 10psi if you threw enough motor, and mods at it.

but in either of these cases we aren't talking about miatas.

If i wrote this how to, I'd only put #2 & #4 on there and elaborate; the rest is just tidbits of random tuning advice.

I doubt it. Turbos can only flow so much air.

And that was the whole purpose of my comment concerning PSI-CFM, it had nothing to do with actual power output of the miata engine with any turbo.

I understood your argument and wasn't countering it.
But you could have worded a couple things a bit better. Like when you said a bigger turbo is more efficient. That's not true, it just has a different efficiency range compared to a smaller turbo.

It's all about pushing air, not pressure.

I took your comment as support actually.


What happened to that dump truck in your avatar? I operate scrapers during the summer months and deal with large machinery like that daily but have never seen one on it's ass end..

If you could design a motor around the greddy turbo, then used n2o or exotic fuels, it could be possible.

Not on the average DIY miataturbo.net budget.

Another to the list....get rid of the Vortech. Either go Begi or a piston type, or go with a standalone. I'm seeing 15psi of fuel variance on my pressure guage depending on outside temps. The warmer it is, the less pressure I make coming off my vortech. I tested my clamping pressure today with the vortech out of the loop and my fuel pressure is stable and capable of 95psi. I installed a brand new Walbro GSS250 last year.