Testing The Waters
 

Are you guys interested in forged rods (I and H beam), forged pistons (with much lower compression -- 8.5:1, 9.0:1), aftermarket head studs?

8.5:1...but why?

Lots of boost

Lots of wasted energy while needing more boost to produce the same results with higher compression pistons.
@SkAsphalt

Mmmm this was written poorly.

50psi?

I run 9.0:1 on 28-30psi for 500whp

I think 9.0:1 will be the way to go. ***for big boost applications***

10.5 would be a good choice for a more conservative approach on lower - moderate boost

with di and e85 i don't see the need to go lower than 10:1, just means the turbo has to work harder to make the same power.

ya i think 8.5:1 pistons went out with primitive tuning. anyone remember the days of stock injectors and fmu's? 10:1 with actual tuning would be perfect.

btw, will these be house brand? or something from arias, wiseco, je, etc.? IMO, these products will be very beneficial for this platform so I vote yes!

Yes.

Very interested.

Someone else actually gets this. :clap:

Chaps

Making power on a FI can go a couple of routes

its a balancing act and always has been

if you have a a high static compression you run a bit less boost and possibly a bit more spark

if you have lower compression you run a bit more boost and bit less spark -

so yes you typically will experience less lag on the former solution but also you will be limited on the amount of power you make

other factors such as bore size, combustion chamber shape, fuel mix formation, rpm, torque curve shape etc etc all come into this

every engine is different and even then there's no 'right' approach - just different techniques with different compromises

I've always heard that you want lower compression with turbo, so there is less chance of "detonation" and knock. And that you want higher compression for s/c or just n/a.

So yea this makes sense to me. But I don't really quite understand what I'm talking about anyway.

Still, I wouldn't put a turbo on these stock high compression engines.

That's the whole point with these pistons. They lower the compression to allow much more boost or the same boost at safer levels.

Why These Engine Internals Are Crucial For FI Or N/A On This Platform According To Jason :D


***The below is based on theoretical numbers. There are so many factors such as supporting mods, lbs/min flow of any given turbo, altitude, blah blah blah. So basically what I'm trying to do is just point out the advantage for these internals to people who may not know***


Here's a rough calculation based on my knowledge (depends on altitude but this is an average corrected based on 14.7 sea level):

A stock FA20 has a high compression 12.5:1 -- So when you add an AVO Turbo kit at 8psi, your actual compression is approx. 19.3 at boost (8psi). This is a potentially high compression amount and a little sketchy IMO

Seeing that this is a high compression, you have to run 93 octane to keep engine knock away. Although, any turbo car typically needs premium gas for that reason so no change there and it only makes sense as boost increases to run a "safer" fuel.

AVO Kit on 93 octane tuned by Drift-Office with full supporting mods made about 300whp on a stock engine with the OEM base compression of 12.5:1


Let's change that base compression now!


Take the same stats but with a different base compression. Let's say JE or CP pistons at 9.0:1 compression.

At 8psi you're only running 13.9 compression ratio at full boost!! That's almost stock lol

So that means with aftermarket internals at 8psi, you're running potentially 300whp at much lower compression/much safer for the engine



So that gives us two options:


1) Run the same boost from available turbo/supercharger kits at extremely safe compression ratios making it much more reliable

2) Running 19-20 compression at full boost which seems to be OK...


What PSI can you theoretically run with a full boost compression of 19-20 starting with a base compression of 9.0:1 ???


18 PSI


That is 10 more PSI than you can run on the stock engine, more than DOUBLE. While there may be a bit of lag (common with any turbo car), the maximum power will be significantly higher. 8psi versus 18psi is an enormous difference depending on the turbo

Now, the flow of a turbo and maximum potential are all factors but just for numbers sake, you could virtually run more than double the boost.

That brings us to our final items that are out for internals, Darton Block Sleeves and ARP Head Studs. The head studs are going to be out soon, ETA TBD. No one has really tested the stock block yet so it's hard to say what the maximum would be. However, I've run those same Darton Sleeves on the 4B11T platform on T4 6466 twin scroll turbos making 700whp so there's no question they are the way to go for very high boost. ARP Head Studs are that extra protection to keep everything fastened and not lift the head in high boost. Any piston blow-by won't lift the head, or it will take quite a bit.

So bottom line, these internals by lower the compression and being forged, can let you run current available boost from kits much safer, run much higher boost for biggg powwwaaaa or handle race abuse if you want to keep stock compression.



What If I'm Staying N/A?

These pistons are all customizable so even if you're sticking N/A, you can add these to your setup at stock compression (or even 11.0:1) to give yourself that forged internal safety for racing applications. They can handle much more abuse than stock internals making it a really great choice.



I hope this helps, as I said, it's all theoretical and there are many factors but this is a rough idea as to the advantage for those who may not know.


Cheers,
Jason :cheers:

Some okay information there, but left out some key points.
In the example comparing the avo kit at 8pai at different static compressions, the one at stock compression will be much more responsive and nicer to drive. Both on and off boost.

Another argument is that, why not just run ethanol? If it's not available in your area, but it in buy the barrel and keep it in your garage. Have a pump map, and a ethanol map.

You're not using more than 300whp on the street anyway. If you think you are, you probably have TRC on and don't realise that you're not actually using all the power.

I'm not knocking the kit either. Just making some comments.

I think its good these kits are being developed, it puts more options out there so we can all achieve what we're trying to.

I'd have to disagree on both those points unfortunately.

Not many people want to be rolling barrels of fuel in and out of their garage and refueling like that. I don't have ethanol available, and quite a few places don't (sadly).

As for static compression, I disagree. High compression and running boost is just asking for trouble ESPECIALLY running e85 where the blends change. You have no idea how many engines I've seen go because tuning on e85 with the blends changing throughout the seasons causing knock and detonation. Running a static 12.5:1 engine with an 8psi turbo running 19-20 compression ratio at full boost is a dangerous game IMO

On top of that, most of the available turbos are so small that they spool EXTREMELY quickly. You wouldn't notice any lag or difference whatsoever. Now, if we're talking some HUGH turbo then yes, but you would have to have lower compression pistons to do that anyways.

Also, using fuel power on the street, I always use full power lol What's the point of having it if you're not using it? haha :burnrubber:

Ultimately, these internals are customizable as well and one does not have to go as low as 9.0:1 either. I just used some basic ideas to convey their use. They're even useful in N/A applications. I was just trying to make a point.

IMO, this car needs a turbo. I've driven many and the FI are totally a different beast. It just seems right. Now, on a stock engine that is 12.5:1 non-FI from the factory, that's pretty sketchy so enter aftermarket internals. You can keep boost lower for quick spool and good response with a smaller turbo like the AVO for example, but keep the full boost compression in a much safer zone also allowing you to potentially use non-93 octane (but always ideal for FI).

@Jason great write up!! Can you elaborate more for peeps who wants to stay NA for the track and wants to rev up to 9-9.5k rpm, how to build the internal towards this?


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Hey Jeff!

Sure thing. Basically for anyone really tracking their car, most engines in stock form are okay over time with proper maintenance. However, adding an intake (or panel filter), full exhaust, tuning, alternate fuel, ignition, etc. are all factors in increasing heat and wear.

The OEM internals have specific metallurgy specs requested by engineers when designing the engine. Considering this car is geared for tracking and having a good time, I'm sure they're pretty good. Then again, a high compression ratio OEM tuned to max potentially can wear on things over time.

In the EvoX world (albeit a factory turbo car), we saw tons of failures on cars with simple bolt-ons because the rods were CRAP! Many bent rods causing catastrophic failures.

I even read of a guy on here that bent a rod on his FA20. For me, even in N/A form, you can go nuts and race while having that extra protection knowing you aren't going to bend a rod or blow up a piston (it's still possible, but definitely far less chance than with OEM).

Also, by adjusting the compression even on a N/A engine, you can play with the timing and move the power band around. So for specific track applications, this could be a major advantage especially if you know your gearing and where you're in the power in and out of turns.

Then sometime down the road, I'm sure we'll eventually see cams and valvetrain goodies allowing the RPM to be raised -- all this will work hand-in-hand.

Make power at 9k or just rev to 9k? Can our stock cams be tuned to make any power that high? I would think a different intake manifold/valve train. Plenty of write ups on how to make high reving engines. It isn't lower compression, although forged internals don't hurt. New head bolts would help.

Most Dyno's show power declining in the 7k+ area. Now I'm curious if anyone has built a high revving FA20!

Ya, it would be so sweet to rev to 9k rpm with power all the way on the track!!


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I'd guess the reason we haven't seen tons of NA improvements is because all this easy powaa from boost. DAMotorsports has talked of Cam's. No dynos or any type of real info though.

FA20 is still new. More NA stuff will come I would hope.

Cams might not do that much on an N/A aside from moving the power band higher UNTIL we get some valvetrain items going to allow high RPM. That will require other mods like oil coolers, catch cans, etc. but N/A will be a bit costly to make over 200whp IMO. Adding a turbo with some lower compression internals will yield much better results, and much safer. 12.5:1 is damn high, especially if you start revving that up. The heat would be quite a bit at 9-9.5k rpm.

Well that would explain why they dyno'd the car a few weeks ago and never showed anything.

Could just be they're under a NDA. I would hope no one wants to run a boosted application up that high.

I'm running 30 psi @ 9000 rpm :D

Based on factory turbo DI engines, I would think 10.0:1 would be ideal. Maybe 9.5:1 in CA with crappy 91.

Most factory 4-cyl turbo engines are actually 8.0-9.5:1 (4B11T, EJ207, EA888, etc.)

Except that if the engine makes 300whp on 8psi with 12.5:1 compression it's going to make a substantial amount less on 8psi with 9.0:1 compression.

More boost means you're heating up the incoming air more, higher IAT's can also cause detonation.

Ultimately you have to tune for the setup, but there's no reason you can't run higher c/r's with boost.

You can't compare how a built engine takes power compared to one with stock internals, I would bet that peak power output on a built engine with 12.5:1 pistons would be very similar to one with 10.0:1 pistons, but with less lag and a broader power band.

Just so you know, the average amount of boost run on a honda k series is 12-14 psi on stock internal and this will last literally years at this power level.

That's a static compression of 19.98:1 @ 12 psi and 21.48:1 @ 14 psi.

There are even quite a few cars running slightly more than this successfully for long period of time (16-18 psi)

Truly, it just sounds like the stock rods and pistons are a weak point in this engine, as the static compression ratios you're talking about really aren't that excessive.

and honestly those compression ratios you speak of are the effective compression ratio, you can't have a static compression ratio with boost, as the boost isn't there :D

As I mentioned above, there are very few turbo applications with high CR's. It's too risky. That's why these kinds of parts exist. You can run small boost on a non factory FI engine, but you can make it what it should have been.

Also, it will make very close to the same power, and much safer. maybe 20-25whp difference, but it will also allow much more boost to exceed even the original 300whp and have a much safer CR under full load

Yep my SRT-4 is 8.1:1 from factory and can run about 22-23 psi safely on pump gas. Im running around 26 right now with a little bit of meth :burnrubber:

Your static compression affects full boost compression which was my point:

http://www.goodvibesracing.com/Compression_Ratio.htm

And a Honda K series isn't an FA20 so you can't compare them. They also start burning oil like crazy those K series and don't last under racing applications. Any race series K has forged internals and a built valvetrain.

Also, what I was pointing out is simply (as I mentioned, this was all just numbers and theoretical data): lower the compression for a boosted application keeps things safe as well as having forged internals for racing applications

This car has a lot of untapped power and running 12.5 compression is not the way to go for any big power. Even bigger muscle cars run in the 9 CR.

Shhh don't say that here, everyone wants to run 19.5:1 compression @ 6-8 psi

:scared0016:

If you look at an SRT4 with a stock turbo, they make about 230whp on ~14 psi, from a 2.4L engine. How much boost does it take to make 230whp on an FA20, WAY less than 14psi. Who cares if the engine can take twice the boost if it needs twice the boost to make the same power? I'm guessing about 3-4psi would get you above 230whp easily, with way less heat than running 14psi.

Boost amount alone isn't the full story.

How does the SRT4 respond to throttle off boost? Hint, it's not great.

@STV3 - how much power are you making on 22psi?

You can't compare the two. It's not the same turbo, one is a factory turbocharged engine and the other isn't.

IE. while he's make 230whp at 14psi, that's downtuned from the factory. He's probably making about 350whp now at 22-23psi and the engine is easily capable of that (MOPAR STAGE III).

Whereas the FA20, yes you can make 280-300whp fully tuned, full bolt ons on 8psi. However, that's the most you can do before it blows up. Try running 14psi on your stock FA20 and let me know what happens. Bye bye engine

So that brings me to my point all along.....allowing the FA20 to run 14-20psi with proper LOWER compression and forged internals would be pretty damn potent wouldn't it ;) Lot's of untapped power and potential here. I'm betting 9.0:1 on this car at 18-20 psi would make in the 450whp range with a proper turbo/intercooler setup.

I dont know because my car was tuned on 26psi and made 417whp 415tq. When I am not in boost it drives no different then my FRS. If I were to swap to a larger aftermarket cams then I may have some low end torque issues but that is not the case.

My point was that it's a larger displacement engine making less power on way more boost.

The key to holding together with more power is stronger internals, not a lower c/r. Give an FA20 forged internals with 12.5:1 c/r and it'll hold a lot more power than the stock internals too. Sure tuning isn't as foolproof, but that's not a good reason to not do it.

I'll take harder tuning to get way better throttle response off boost as well as less lag and cooler IAT's every day of the week.

Also my block, internals and head are bone stock

That's because Dodge way over built the engine stock, they're known to be very strong from the factory.

It doesn't hold 400whp + because of the low c/r, it holds it because it has very beefy internals stock.