Quite surprised no one is talking about this subject , I think Turblown said a while back they were going to post a Dyno to compare but never actually did .Is the difference in lag big ? I started by considering the 7670 but then I was swayed towards the 8374 so now I really don’t know if I would sacrifice even more responsiveness ; plus I heard that the 8374 is more suited for a 13B

Thanks

 

This thread compares the 8374 and 8474 pretty extensively - https://www.rx7club.com/single-turbo...hread-1138737/

 

Thanks but I’ve read that ; besides some helpful little snippets the whole thread is a pissing contest on who knows more about physics ,Dynos and the 9280

 

8374 is the way to go. On the 8374 vs 8474 unless you do 2 cars back to back with the same setup you wont really know. the chance of that happening is real slim.
In theory the 8474 will outflow the 8374. by how much exactly in the real world. it is hard to say

I have been plenty happy with my 8374. response is just phenomenal.. the 8474 might be a little laggier but i dont think it will be a substantial difference between the 2

 

8374 is beter for what I want and thats what I gather from different sources. I am not going for 500whp , but I want to achive 400-450 whp at about 13-14 psi with good spool.

 

i would try to attempt 500whp in an fc since people say that after you have to throw a lot of money to strengthen the internals but from what I gathered is that the new “versions” of the turbos are better for maxing out . I’ve read somewhere that if you’re hellbent on 600whp and not willing to use an Efr 9xxx , then the 8474 is the better turbo , so yea , I think I’d go with the 8374 too.

 

The 8474 is showing to be about 250 rpms slower than 8374, not a huge difference. I have both turbos and a car ready to dyno test etc, just need time. Buried here.

 

we do have a fc in cyprus ~480whp with a very old setup(p-trim gt35R), stock motor, stock internals. owner has been pretty happy for several years with no issues. so as far as "strengthening" the internals i think you ll be fine with a properly built motor. the tune is the major keypoint. with that being said, the first to give at that power level is the transmission

 

For those numbers expect 15-17psi unless you have a large port or e85.

 

You can't have the best of all worlds. If they made a turbo that had a lightning quick spool and makes 450 rwhp on only 13-14 psi, i'm sure we'd all own it.....

If you only ever want to make 400-450, I would go 8374. If you want to make 500+, I would go for the 9180 (or 8474).

 

I do have large street ports. With the sxe362 The car made 393 whp on dynodynamic at 13psi. My only expectation would be faster spool and a little bit more torque than 300. I have water/meth injection, but for safety only. If I have to go up to 15 psi its not big deal. I am realy excited about it, especially to see how it will behave with different turbo manifold.

 

The turbo is just one variable of the equation in any set up. I dont know how much you know or are informed, but efr are the fastes spooling turbo you can get and provide great power. Again, it depends on your set up.
400whp on dynodynamic dyno (maybe 440rwhp dynojet). I am almost sure I can achive 450 on 14psi on dynoyet, but i am going to use the same dynodynamics dyno that I have been using.

Aaaanyway thats all the power I want thats why I chose the 8374.

 

I highly suggest you stop comparing dyno numbers and go to a drag strip. A legit 400 whp FD on old school dyno dynamics before all the software upgrades to skew numbers to compete with dynojet would trap 130+mph easily in the 1/4. On 14psi on a 62mm turbo you are going to be lucky to trap 125mph. EFRs have drastically changed the driving experience on the street and make a great power curve but have not changed top end power. Actually, the same size precisions seem to have a noticeable advantage on top end power.

 

I am agree with you on dyno numbers, but thats my only measurment tool i have and i am not interested on drag(dragstrip). Thats why i said what i am expenting numberwhise. If I was interested on drag I would go for max power and not for 400whp. Thats all Dj

 

That is by far the best way you could compare, "same car" change over and retune using the same type of ignition advance as the previous tune to try and compare the apples with the other apples. Slightly larger compressor should give a increased mass flow equalling in more power for that given rpm point. There should be a direct correlation with the compressor charts and the end effect. Providing that the compressor wheels share the same aerodynamics off course, I say this because Im assuming that the compressor wheel efficiencies have stayed the same. It's not uncommon to find a compressor jumping up in efficiency due to a later change. That being said if the compressor wheel has changed efficiency in the upwards trend your ending up with a turbo that produces more mass flow with better air density which equals More power.

 

... expecting this thread to launch into 9280’s in 3 ..., 2 ..., 1 ...

.

 

We haven't really discussed twin 9280s yet...

 

was that quote directed at me?

 

I agree here, 100%. The EFRs are good street turbos for what they are, but the hot side wheels are all undersized for the compressor for the high rpm and top end flow capability of a rotary. Increasing compressor without increasing turbine wheel size in an already undersized hot side scenario doesn't buy you anything... unless maybe you're just trying to sell them and making claims without supporting data, in that case the new one is the ****.

They're great turbos that have alot of engineering and analysis driving their design, but all of that was geared towards supporting the larger market of piston motors. If they were to put the same stock in designing an EFR line for rotary engines, the hot sides would be vastly different.

Does it spool low? Sure... but at the expense of high rpm power, which is where you win with these engines. 500 rpm of faster spool will still have you forking money over to the vette guy who has instant torque but can't pull up top.

Skeese

 

I see people saying the EFRs dont pull up top and it makes my head explode...

So you buy a 420hp sized EFR 7670 or a 550hp sized EFR 8374 or a 700hp sized EFR 9280

And then you complain that it makes its peak power rating too LOW in the rpm range?

Or are you just wishing they made a turbo rated over 700hp rotary and are retarded at explaining that?

 

I can see where this is going.. another useless. Whay if this turbo,? What if max power? What if its not perfect?
roll with what you love..
Me, personaly i want it for the street at about 400hp with faster spool than my 362sxe at the same psi. am I going to accomplish my goal?..I almost sure.
All comes down to the purpose of the car.
In my case is perfect for me.
And who is talking about racing vettes?

 

Yeah the efr still seems to be the closest thing to no trade offs.
my ewg 8374 spools up and does NOT run out of legs up top on pump gas tune. Probably as much usable power band as an ls engine. But its a rotary.