DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Whatz my max boost I can run!!??

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Old 05-15-2010, 06:17 PM
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Default Whatz my max boost I can run!!??

Just kidding, but I would like an opinion. Would I be safe tuning for 12 psi on my setup? Here it is:

94 drivetrain (about 80k) with 550's (everything else fuel related is stock) run by ms and lc1.

tubular manifold, t3/t4 50/84 (to be replaced with a t3/t4e 50/48), 3" turbo back. 11x16x2.5 intercooler with 2.5" piping.

coolant reroute (with heater core), koyo 36(ish)mm rad with twin slim line fans (2200ish something something somethings), 185* tstat

The car is mainly a weekend toy/autox and contemplating dabbling in events at limerock.

Last edited by astroboy; 05-15-2010 at 06:19 PM. Reason: wtf I use the car for
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Old 05-15-2010, 06:21 PM
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There is no way to tell but with a good tune I don't see why not. There is no "yes or no" answer to this ****.

On another note: why a 185 tstat? all its doing is causing you to warm up slow as ****
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Old 05-15-2010, 06:26 PM
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Really? You think i should have the 195* in there?

I also understand with a good tune most things are possible but want to keep it at that safe to not blow up yet fun level. I will also have a good tune complements of some solid local talent (240-miata)
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Old 05-15-2010, 06:52 PM
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Once the thermostat is open its open. Whether it opens up at 180 or 190 wont matter if your cooling system is not capable of keeping the temps down.

I know this cause I tried a 180 stat in my car. Worthless. Went back to stock temp one. Should have listened to the smart folks on here telling me not to bother.


And again, if you are conservative (rich fuel, low timing advance) the car should be ok on 12psi. Or you could lower boost and advance timing/lean out fuel. Its a balancing act. Too much of any one of those three things will lead to detonation which will assrape your motor
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Old 05-15-2010, 08:44 PM
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My motor doesn't have an ***.
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Old 05-15-2010, 09:42 PM
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Originally Posted by astroboy
My motor doesn't have an ***.
Noob.
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Old 05-15-2010, 10:47 PM
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Yeah! Some elaboration that highlights my noobishness?
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Old 05-15-2010, 11:12 PM
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Originally Posted by astroboy
Yeah! Some elaboration that highlights my noobishness?
You drive a Miata, therefore you are gay, therefore you give it to your motor in the ***. Or you're the catcher, that's fine too.
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Old 05-16-2010, 08:42 AM
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Ok, well then I'll pitch. Do I get to pick which motor I assrape? If so I will go with the passenger side headlight motor. The fuel pump and windshield wiper motors are probably too worn out for me.

So on the pressure topic I am not trying to run 12 psi to say I am running 12 psi. I would like to tune for 12 psi and not have my engine fail but reap the benefits of a higher pressure; unless there are no benefits but won't find that out until we start tuning. So with a good tune (not tuning it like a ***** keeping it scrooge mc duck rich) will I make my engine meet an untimely end or will the stock bp take the punishment?
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Old 05-16-2010, 11:18 AM
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Originally Posted by astroboy
I am not trying to run 12 psi to say I am running 12 psi. I would like to tune for 12 psi and not have my engine fail but reap the benefits of a higher pressure
Does not compute. Why are you focusing on a certain psi? Do you know the general rule of thumb of how much hp the bottom end will take? Focus more on getting a reliable tune making the power you want and less about the pressure it takes to get there.

I'd suggest sticking with doable power levels with a good tune, it will save you a bunch of money on transmissions.
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Old 05-16-2010, 01:28 PM
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My thought process was to tune up to 12 psi and see if it made decent power to that pressure. If it seemed to make similar power as 10psi then I would only run 10psi. I was also thinking if the general consensus is the stock block will not take 15psi would everybody think the same about 12psi. I guess I am trying to figure out what pressure should be my stopping point before I blow something up. I thought the reliable power level for these engines was in the 250hp range for a stock engine...same goes for the transmission. Correct?
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Old 05-17-2010, 04:25 PM
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What? read faq noob. Your transmission will suck and die.
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Old 05-17-2010, 10:03 PM
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Fine, 220whp.
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Old 05-17-2010, 10:18 PM
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Lower.
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Old 05-17-2010, 10:25 PM
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Just remember I bent a rod at 200 :(

I have your timing fairly conservative and you are still running 11.6-11.9 in boost so you are safe. . . But id say dont shoot for more than 220 rwhp... whatever that equates to in PSI.

Ill be around more to help you again after I replace my blown 5spd.
Yes that is right.... I BLEW MY TRANI at autox. Good thing I didnt borrow your Rcomps, huh?
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Old 05-17-2010, 10:56 PM
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**** it. Probably most boosted miatas have bent rods. Don't be afraid. Just do 15psi and order a 6 speed. /thread
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Old 05-17-2010, 11:00 PM
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Originally Posted by 240_to_miata
Just remember I bent a rod at 200 :(

I have your timing fairly conservative and you are still running 11.6-11.9 in boost so you are safe. . . But id say dont shoot for more than 220 rwhp... whatever that equates to in PSI.

Ill be around more to help you again after I replace my blown 5spd.
Yes that is right.... I BLEW MY TRANI at autox. Good thing I didnt borrow your Rcomps, huh?
Welcome to the "Iblewmytrannythisweek" club
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Old 05-17-2010, 11:17 PM
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Why would any guy admit that they blew their tranny? IDk about y'all. I think I am just going to be conversing with y'all online for now on.

Have a great day,
Jared
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Old 05-17-2010, 11:20 PM
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12psi on a t3/t4 is quite a bit more cylinder pressure than 12 psi on a 2560. I think you will bend rods if you don't crack ringlands first. I'm not being cynical, by the way, I've just seen this discussion a few times in the past. It usually ends within the time period of one week to one month. But I wish you well.

Do you know how many lbs/min of air you will be administering with that turbo at 12psi versus a 2554 or 2560 at the same psi? You might should compare just for grins.
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Old 05-17-2010, 11:32 PM
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Originally Posted by 240_to_miata
Just remember I bent a rod at 200 :(

I have your timing fairly conservative and you are still running 11.6-11.9 in boost so you are safe. . . But id say dont shoot for more than 220 rwhp... whatever that equates to in PSI.

your Rcomps, huh?
On a 1.8 at 200whp? How long did that take to occur? Too much torque?
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