Built Engine Max Boost
 

I will be building up my miata in the next week with the belfab kit. Roughly 9:1 compression, rods, valvetrain, EXintake mod, Cam gear, etc... I know on the stock block 12psi is safeish, 15psi is pushing it, and 18psi is a ticking time bomb. When it comes to built motors I can find less input on what they handle.

So with all supporting mods and with a good tune, what can a typical built bottom end handle. Remember this is roughly I know all about different turbos, timing, intake flow, transmision, differential, etc... Thanks

You can run more than 18psi with built motor. But transmission becomes a issue after 250whp.

With forged pistons and forged rods, the limit is no longer the engine. The drivetrain behind it becomes the limiting factor.

I am well aware of the drivetrain issues with these cars. I have owned another miata and have built many a cars. So thank you for that information but my question still is how much can the ENGINE HANDLE?

Given how little sample data there is it'd be terribly irresponsible just to throw out some approximate number.

Maybe you should go talk to that dude who built the eliminator miata who's running ~500+hp on his 1.8

Who knows? There is no definitive answer. A few have done 400, 500, and 600whp setups with built engines. Those are not necessarily the MAX ENGINE HANDLE per se. These are just numbers that have been put down.

Thanks for the info. Anybody else have any experience/input. Although I think the turbo I will choose will limit me since I don't want to sacrifice too much lag. Although I could always add a small nitrous shot:firedevil

Lots of people do. Learn to use the damn search function and maybe you'll find their input too.

Maybe I have searched and seen that they do. WTF did it have to with my thread and your unnecessary rudeness. Which when searching I have found ALOT of.

Asking how much boost a motor can handle is not a very good qurstion. 15 psi on my 2854 is a hell of alot different than 15 psi on a 3071. Tell us what turbo you plan to use and then you might get a more accurate answer. Although you could just search.
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I haven't decided fully on turbo yet so thats why I am asking a general idea. And I have done a search and there is little information on the breaking point due to limitations of engine.

41lbs

Chucky, your questions are weak, and very noobish. You've already had some of your post deleted because they were crap. This is borderline.

In a sense, you are being rude posting questions that can be answered (indirectly) by searching. So expect some hazing. The fact that you put "max boost" in your title shows your lack of understanding.

If you are anywhat worried about lag, then you're not worried about how much power a built engine can take.

I rest my case.

Max boost is a very scientific term. They are not weak or noobish. Hell one minute after I started this thread another member with thousands of posts asked the same question.

I have only been rude when people were rude to me first. I have thanked people when the gave good info and told people who wasted my time to piss off.

There is a balance between power and lag. I need to know the max boost a engine can handle so that I can compare what turbo can put out that much and see how much it lags. Then go down the ladder untill I find a happy medium. Wow don't know if this forum is for me at all!

Also if you find me 5 threads were they talked about the limitations of the block with a fully built bottom-end I will admit i'm wrong. It the one started 1 minute after mine doesn't count.

This is where your main problem lies. As has been said in this thread already. 15psi from a gt2554 is much different than say, a gt42r. Therefore, a number of max boost is irrelevant unless you had already chosen a turbo.

Wow that is so not true. If someone tells you he was running a gt2860 at 25psi and it he bent a rod you can tell that if you run a gt30r at 22psi the flow will be the same so the limitation is the similar. Also at the beginning I said I knew all this and this was a rough estimate.

Wrong. On several accounts. You need to respect all the senior members of this forum, even the ones that are being rude to you. Underneath their rudeness is good advice. Regardless of what you think, they're right. 6 months from now you'll look back at this thread and laugh, and realize what a dick you were and how you should have taken Sav's and other "haters" post more seriously.

Also wrong about max boost. Boost :ne: power. Boost is a measure or restriction. When selecting a turbocharger for an application, you first decide on a power goal, then look at various turbos that will get you to that power goal.

AGAIN, IF YOU'D SEARCH ALREADY YOU"LL FIND ALL THIS INFO IN THE FORUMS FAQ! HINT HINT!

And if you'll look at the guy that asked "the same question" you'll see his title says POWER, not boost.

yes max boost is a scientific term but for what. my build motor can take everything my 2854 can throw at it and not break a sweat (providing a good tune). What psi that is I have no idea. Like I said earlier 15 psi on a 2554 is worlds different than 15 psi on a 3071.


Lets try this. What are your goals with the car? What do you plan to use it for? How much money do you have?
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No just because I am new to this forum does not mean they can be rude! Power varies way to much to be a comparison. Boost is more accurate because it accurately measures the maxium pressure that the engine can handle.

A car can have 500hp and 400hp but be only running 30psi. Both of which would blowup at that same psi but not hp.