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Originally Posted by Tcoat
To be clear that is the FA24F they are talking about. Just because it is the same base engine code does not mean it is the SAME engine. Who knows what they changed for internals.
The FA24F has a compression ratio of 10.6:1. That is a huge difference that can not be ignored.
We will know what they can do eventually but saying they did this that or the other thing to the F is almost meaningless.
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Sorry, rereading what I wrote, I can see how that is confusing. Sounds more like ramblings that a clear argument.
What I wanted to say is that the FA24F could reasonably hit the values they achieved without having to make dyno manipulations, and I say that based on comparisons to the FA20D's stock power and "reliable" power potential and the FA24F's stock power. I was also saying that power could be even higher on the FA24D when boosted with E85 because of the higher compression, assuming the internals could handle it of course, but I didn't state that.
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Originally Posted by StormFalcon
Ah I didn't realize it was different. My point was just that even if that dyno run was exaggerated, it seems reasonable that the engine could be hitting 3-400HP on E85, which in my mind would be enough. I guess we'll just have to wait like 2 years to find out
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We don't know what is different besides the D4S and turbo system. We can make a guess, but we don't know. The FA24F comes with more power and torque than the FA24D, but the FA24D comes with higher compression, which has its own risks. What we do know is that the FA20F and FA20D have similarly sized rods, where the WRX/FA20F's rods are slightly larger/reinforced than the 86/FA20D's, and yet, the WRX comes with 268hp and 258tq, which is a lot more than the 86. Interestingly, the specs on the FA20F is not too far off from the Ascent with the FA24F at 260hp and 277tq. It seems like the rods on the FA24F would be similar in size to the WRX's or maybe slightly more reinforced, but according to the link, the guys are saying that the rods are a lot beefier. Does this mean the FA24D's rods will also be a lot beefier? We don't know.
Again, we don't know what is in the FA24D, but it is likely the higher displacement and higher compression means the rods might be reinforced enough that the power potential will be raised compared to the FA20D. I wouldn't be surprised if the car will handle 400-450whp from the 350whp that the FA20D can reliably handle.
Quote:
Originally Posted by Tcoat
The FA24F is a low compression, direct injection only, turbo engine. It brings it torque and power on way down low in the rev range and is for all intents and purposes a truck engine.
The FA24? is a high compression, direct and port injection NA engine. It brings it's torque and power in at high revs and should be a very nice sports car engine.
The FA24? should work really well on E85 but looking for 300-400HP out of it with a tune and some bolt on's is very optimistic.
What they can do to the one doesn't mean much when compared to the other.
OH and they were running 22PSI on that heavily modified FA24F to get that 500HP. Try doing that on an engine with a 13.5:1 compression ratio and you will be finding parts of the block and rods for several blocks around you!
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I've heard this phrase before, "for all intents and purposes a truck engine." What do you mean? Are you saying that because it has a fast spooling small turbo for low end torque? Does that mean the MKV Supra has a truck engine too because its torque comes on fast down low and fades up top? Does this mean the Accord 2.0T has a truck version of the CTR motor because of the smaller turbo, decrease in horsepower, but increase in low end torque?
Typically a truck motor is heavy like cast iron vs aluminum to keep reliability high and cost down. Typically a truck motor is a low stressed motor by having less aggressive compression, less aggressive cam profiles and less flow to the heads. Typically a truck motor is low revving and high torque, which it achieves through an undersquare design, but even if it is not undersquare, there is a long stroke on the motor.
Let's consider the FA24F now. It has an aluminum block. For a turbocharged car, it has relatively high compression. The engine is undersquare, and at 86mm, the stroke is relatively short for a "truck engine". The motor revs high enough--higher than a truck engine typically would. I wouldn't call it a truck motor. I would just call it a typical passenger car motor--not a sporty car motor or a truck motor. Just saying. Seems like anything that is not a sporty car engine is a truck engine to some.
Oh, and they weren't running a heavily modified motor. Essentially, it was a stock longblock with ARP head studs--no internal upgrades--just bolt-ons. Yes, it had several bolt-ons, but there whole point was to test the limits of the stock block and stock injectors, which is why the upgrades are headers, turbo, FMIC, exhaust, intake, etc. The high compression on the FA24D is not necessarily a deal breaker for turbocharging, which is what I said earlier, that E85 is very good at protecting the motor from pre-ignition. Many people with access to E85 don't drop compression when building the motor when going for 500whp+. Several tuners here say it is not necessary to drop compression, as E85 deals with the issues. This could be true for 13.5:1 too if Toyobaru cleverly engineered the motor or if the larger pistons act as a heat sink or increased the surface area to aid combustion or some wizardry. The big thing will be if they reinforced the rods enough to handle the power. They obviously increased the rod size per this quote below compared to the FA20. They didn't specify if they mean the FA20D or FA20F, but I will assume they mean the FA20F. Regardless, the rod size on the FA20F wasn't too different to the rod size on the FA20D, and the FA20F and FA24F make similar power, so we could see much beefier rods on the FA24D, if we are following the trends. So maybe the engine won't go kaboom.
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The rods are still J shaped but way beefier
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