max horsepower on 13BT block
03-13-03, 11:32 PM
#1
max horsepower on 13BT block
I've owned quite a few RX's ; 4 first gens, 2 second gen T II, and 1 third gen. Right now I'm back to a mod. first gen, and about to put in my 90' motor after it gets rebuilt.
My question is this;
I know the fd3s motor has the strongest side housings and support up to 650+ on gasoline. Without additional dowel renforcement.
How much can the FC3s side housings take?
I heard on a few occassions that they are only able to produce 400 hp reliable.
Is this true? Of course lets say the fc3s is fully built with 3mm and all that, but not including any extra dowel pin mods. Do the 89-91 (GT-X) housings take more power than the 87-88's (GT-R)? What is the proven HP limits of both?
My original plan was to use FD side housings with FC accessorys, but after seeing how much difference the ports are, the manifold was, I didnt go through with it.
Please someone write back about this.
Oh yeah I'm talking reliable power, I've seen a few Fc pushing 500+ but for how long?
Thanks guys, Logan
My question is this;
I know the fd3s motor has the strongest side housings and support up to 650+ on gasoline. Without additional dowel renforcement.
How much can the FC3s side housings take?
I heard on a few occassions that they are only able to produce 400 hp reliable.
Is this true? Of course lets say the fc3s is fully built with 3mm and all that, but not including any extra dowel pin mods. Do the 89-91 (GT-X) housings take more power than the 87-88's (GT-R)? What is the proven HP limits of both?
My original plan was to use FD side housings with FC accessorys, but after seeing how much difference the ports are, the manifold was, I didnt go through with it.
Please someone write back about this.
Oh yeah I'm talking reliable power, I've seen a few Fc pushing 500+ but for how long?
Thanks guys, Logan
03-14-03, 12:00 AM
#2
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the 89-91 is stronger then the 86-88.
but I've senn a few crack around 400RWHP.
I still really think it's from detonation though. if you tune it right, it should take it.
but I've senn a few crack around 400RWHP.
I still really think it's from detonation though. if you tune it right, it should take it.
03-14-03, 01:34 AM
#3
max output you should really lay down is about 450hp anymore than you need to dowel your engine to hold more, that's why FDs are so strong, they got dowels in the weak spots of the 13bt rotary.
03-14-03, 10:48 AM
#7
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If you aren't tuned, you can blow a doweled 13BREW just as easy as a stock 13BT.
It's all in the tuning. NO detonation will make reliable HP.
I will be testing my theory soon! Stock S4 engine running 400+ HP with H20 injection.
It's all in the tuning. NO detonation will make reliable HP.
I will be testing my theory soon! Stock S4 engine running 400+ HP with H20 injection.
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03-14-03, 08:34 PM
#9
As long as the 13bT can handle 400 crank HP, I'm happy. I only intend to get up to 400, due to the worry of my stock First gen rear end may not take any more. ( But I always could push it till it breaks
) I also didnt know the 13REW had more dowel pins? My dad and runs a Mazda RX shop, I will check some old FD housings compared to the FC's and see if they truly have more. I'm pretty sure they dont, but finding out will be interesting. I'll post soon with the results. As far as a "hybrid" rotary, I think I will use the staionary gears from a FD and maybe the housings, since the coolant ports are bigger. But yes, I agree the FD block is one hell of a motor.
) I also didnt know the 13REW had more dowel pins? My dad and runs a Mazda RX shop, I will check some old FD housings compared to the FC's and see if they truly have more. I'm pretty sure they dont, but finding out will be interesting. I'll post soon with the results. As far as a "hybrid" rotary, I think I will use the staionary gears from a FD and maybe the housings, since the coolant ports are bigger. But yes, I agree the FD block is one hell of a motor.
03-14-03, 11:33 PM
#12
Keep Right Except to Pass
Have you guys seen this page?
http://my.engr.ucdavis.edu/~pko/13BTvs13BREW.html
http://my.engr.ucdavis.edu/~pko/13BTvs13BREW.html
03-15-03, 10:26 AM
#13
Dowel pins
A dowel pin is located in all rotarys, they are located in the upper and lower corners of the housings. Two are in the front housing and two in the second housing. They serve as a strong pin that goes through the cast iron housings to the aluminum ones and connects them together. Adding more of these will create a stronger block struture, but takes machining and $$$ to perform, and I'd only trust a specialized shop to do it.
The dowels run parallel to the tension bolts. Tension bolts run through the entire block in a circle pattern around the housings. their is about 12 or so tension bolts, but I cant remember for sure. The tension bolts hold the motor together in a strong sandwich, the dowel carrys the side loads on the block. Sorry for the long answer, anyone can add on to it, but I think that about explains it
The dowels run parallel to the tension bolts. Tension bolts run through the entire block in a circle pattern around the housings. their is about 12 or so tension bolts, but I cant remember for sure. The tension bolts hold the motor together in a strong sandwich, the dowel carrys the side loads on the block. Sorry for the long answer, anyone can add on to it, but I think that about explains it
03-15-03, 10:58 AM
#16
Keep Right Except to Pass
Originally posted by GtoRx7
Yeah I've read that site, but I wanted other opinions on if it was really true or not. I feel real-world tuners have a greater insite.
Yeah I've read that site, but I wanted other opinions on if it was really true or not. I feel real-world tuners have a greater insite.
Go to the track and talk to the fast rotary guys.
03-15-03, 11:14 AM
#17
Sorry man, I didnt mean to sound so rude. I think the site is great and has the most info about this subject, just I had already read it. Others I'm sure would like to see it though. I was just tring to find out a little more about the diff between the 13bt GT-r and 13BT GT-X, as the site seems unclear about the improvements if there was any, in the strength of the side housings. Sorry again, the site is helpful. 
03-15-03, 02:07 PM
#18
http://fc3s-pro.com/TECH/FAQ/deton.htm
Detonation in a rotary engine is bad!
As a side note, serious detonation can cause curious indentations on a rotor face, on opposite ends of the "dish" in the center. FC3S Kouki and FD3S rotors tend to do this pretty easily due to their lighter weight and, therefore, less mass and metal thickness at the rotor face surface. FC3S Zenki rotors seem to be more resistant to this depression damage from serious detonation. The Japan tuners have seem to have caught onto this characteristic, as demand for FC3S Zenki rotors (even with the lower compression of 8.5:1 versus 9.0:1 for FC3S Kouki and FD3S rotors) have skyrocketed for drag racing applications where insane boost levels are seen, typically over 25psi!
03-15-03, 02:29 PM
#19
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I'm not sure if there are more pins in the FD motor or not. but I do know the metal around FD dowels is thicker and stonger. which is where it cracks on the FC ones.
03-15-03, 06:59 PM
#22
Ah, I see the topic of '87-88 low compression rotors finally made it onto this post.
I wasn't going to mention it since I assumed it was just common sense on a very high HP rotary, but this quote wrinkled my brow.
QUOTE-
The Japan tuners have seem to have caught onto this characteristic, as demand for FC3S Zenki rotors (even with the lower compression of 8.5:1 versus 9.0:1 for FC3S Kouki and FD3S rotors) have skyrocketed for drag racing applications where insane boost levels are seen, typically over 25psi!
Hello!! It is not "even w/ lower compression" it is really mainly for this lower compression- whether they realize it or not.
If you want more compression on a turbo engine it is much safer and more effiecient to up the boost than up the compression ratio. "Turbo compression" is more efficient (less heat produced) and can be cooled by the intercooler- whereas "engine compression" is less efficient positive displacement compression (more heat produced for same compression) and has no means to cool it (short of direct injection technology which hasn't hit the rotary development) and this means more chance of pre-ignition and a less dense air charge.
High compression turbo applications are only a concession made for drivability- true performance applications are always lower compression higher boost.
Ian
I wasn't going to mention it since I assumed it was just common sense on a very high HP rotary, but this quote wrinkled my brow.
QUOTE-
The Japan tuners have seem to have caught onto this characteristic, as demand for FC3S Zenki rotors (even with the lower compression of 8.5:1 versus 9.0:1 for FC3S Kouki and FD3S rotors) have skyrocketed for drag racing applications where insane boost levels are seen, typically over 25psi!
Hello!! It is not "even w/ lower compression" it is really mainly for this lower compression- whether they realize it or not.
If you want more compression on a turbo engine it is much safer and more effiecient to up the boost than up the compression ratio. "Turbo compression" is more efficient (less heat produced) and can be cooled by the intercooler- whereas "engine compression" is less efficient positive displacement compression (more heat produced for same compression) and has no means to cool it (short of direct injection technology which hasn't hit the rotary development) and this means more chance of pre-ignition and a less dense air charge.
High compression turbo applications are only a concession made for drivability- true performance applications are always lower compression higher boost.
Ian
03-15-03, 09:29 PM
#24
Originally posted by CrackHeadMel
but how long did his motor last like that? if memory serves it wernt long at all
but how long did his motor last like that? if memory serves it wernt long at all
I dont think ANY 13BT making that kinda power is going to last long. Thats about the upper limit of those motors.
Jarrett
