NoPistons -Mazda Rx7 & Rx8 Rotary Forum

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-   Rotary Engine Building, Porting & Swaps (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/)
-   -   300 Hp build - economically (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/300-hp-build-economically-71622/)

CustomEngr 02-04-2009 10:43 AM

Hello guys, this is my first post here. I know quite a bit about V8's and I know how quickly the $ can add up in a project that's not properly managed. Most people will drop about 1000$ per 100hp in a V8, paying for name brands, shiny this, chrome that, AN fittings and braided lines and platinum plugs with 5 tips on them, when I know I could build one for 250$ per 100hp. It just wouldn't look as pretty.

-BUT..I have no experience building rotaries. I'm looking for 300HP. No more. and I don't care about name brands. (I always liked using parts from GM Performance for my engines. They spent millions of $'s and thousand of hour developing it - 95% of the time OEM works just fine.)



This is just an excercise for me. I have been building custom cars for years and have always been intrigued by the power/weight ratio of the rotary, as well as the insane rpm. 300 Hp in a VW swap, from what I am reading should be as reliable as the sun coming up and fast as a raped ape.



Can you guys post some set-ups and prices (rough estimates). Will a N/A stocker with porting work? but is that cheaper than a single turbo with minor upgrades and no porting? 300 should be an easy number to hit, but which is the most economical? Obviously a non-turbo is more reliable, but custom port work is expensive, right? I'm not looking to do any custom work myself (i'm done with that) I let the experts do it.

I want to have this car done on the road by August. I would like to buy the engine done, or mostly done. thanks.

CustomEngr 02-04-2009 11:15 AM

oh- application: mostly just 'spirited' street driving, and high way use. No drag racing. No track days. Just a flat torque and power curve up high. low end is not important to me. I enjoy high speed racing as opposed to stop light stuff. I'd prefer mid/top end power.

Nateb123 02-04-2009 12:47 PM


Originally Posted by CustomEngr' post='916002' date='Feb 4 2009, 08:43 AM
Hello guys, this is my first post here. I know quite a bit about V8's and I know how quickly the $ can add up in a project that's not properly managed. Most people will drop about 1000$ per 100hp in a V8, paying for name brands, shiny this, chrome that, AN fittings and braided lines and platinum plugs with 5 tips on them, when I know I could build one for 250$ per 100hp. It just wouldn't look as pretty.

-BUT..I have no experience building rotaries. I'm looking for 300HP. No more. and I don't care about name brands. (I always liked using parts from GM Performance for my engines. They spent millions of s and thousand of hour developing it - 95% of the time OEM works just fine.)



This is just an excercise for me. I have been building custom cars for years and have always been intrigued by the power/weight ratio of the rotary, as well as the insane rpm. 300 Hp in a VW swap, from what I am reading should be as reliable as the sun coming up and fast as a raped ape.



Can you guys post some set-ups and prices (rough estimates). Will a N/A stocker with porting work? but is that cheaper than a single turbo with minor upgrades and no porting? 300 should be an easy number to hit, but which is the most economical? Obviously a non-turbo is more reliable, but custom port work is expensive, right? I'm not looking to do any custom work myself (i'm done with that) I let the experts do it.

I want to have this car done on the road by August. I would like to buy the engine done, or mostly done. thanks.



Not super sure on the costs related, but I can bet that 300hp N/A isn't the way you want to go because the porting required to get there is race-porting. You'll get no torque, wicked horsepower if you rev really high, and then your motor will last for weeks...maybe. Get a TII. The exhaust from a rotary has so much energy it's begging to be used. N/A will just dump all that power uselessly.

vosko 02-04-2009 04:42 PM

a 2 rotor with more then 200rwhp n/a is hard to do. VERY hard to do

jwteknix 02-04-2009 05:59 PM

Bnr turbo builds stock hybrids for our car perfect for what your looking for if you have a tII

Nateb123 02-04-2009 07:02 PM


Originally Posted by vosko' post='916031' date='Feb 4 2009, 02:42 PM
a 2 rotor with more then 200rwhp n/a is hard to do. VERY hard to do



I don't know about VERY hard, but certainly a J-port or P-Port is required.

Maxt 02-04-2009 09:26 PM


Originally Posted by Nateb123' post='916042' date='Feb 4 2009, 06:02 PM
I don't know about VERY hard, but certainly a J-port or P-Port is required.

your transmission choice, your choice of gear spacing and final drive ratio will be important with a very extreme ported motor. my p-port makes pretty good power, but the car would be much faster with a 4.77 rear end and a close ratio dogbox.

Are you thinking 300 at the wheel or the flywheel?

fc3sboy1 02-04-2009 11:23 PM


Originally Posted by vosko' post='916031' date='Feb 4 2009, 02:42 PM
a 2 rotor with more then 200rwhp n/a is hard to do. VERY hard to do

200whp is not that hard to do at all. i have built 2 engines now one was for ower EP rx7 and the other is a freinds EP rx7. both run on 87 octain fuel both are street ported 6 port motors, one is carbed with webber 45mm the other is fuel injected with a stock s5 intake with a throttle body mod using motech managment. the fuely ran 210 on the rollers at the wheels max rpm was 9k on a mild street port. the carb motor is around 220whp on a slightly more agressive port reving to 9500 rpm. this one has ceramic 2mm seals . both motors make 160 toqure. again these are street port 6 port motors both have lasted a full season with oil changes and -10 plugs wich are changed regularly.

CustomEngr 02-05-2009 07:40 AM

I was thinking 300 at the flywheel. Of course RWHp/torque is inconsequential as that can be changed with gearing, etc. as mentioned before.



I found a JDM (Japanese Domestic Market) 13B RE on Ebay for 1350$ ! This was a factory twin sequential turbo, rated at 265 Hp. Is that a pretty easy start? Emissions doesn't matter to me.



Do I really need an aftermarket ECU to hit 300Hp? The Motec's I've worked with are NOT cheap.



Basically this is what I'm asking:



What is a decent, but not overpriced:

Intake?

Exhaust Manifold?

Injectors?

Ingnition (I heard you can use the Mallory MSD 6a, right? not a bad choice)

AFM? (if needed)

ECU (if needed)

Plugs? (i don't think anything over 7 psi is needed for 300Hp, right? slightly warmer than stock?)



I have a great exhaust guy, and it is a custom install so no info needed on that.



It will not be a race engine, it will never see a DYNO. The most I will do is put in some race fuel when I go to car shows because I like the smell.





Also on a side note: Do any Mazda 5-speeds bolt up and handle 300Hp, or do I have to adapt a stronger tranny?



Thanks for the info so far!

j9fd3s 02-05-2009 06:13 PM

at 300 hpish, there are 2 ways to do it.



you can take a factory turbo engine, like the REW, buy an ECU, and maybe a single turbo. depending on the turbo, 300hp is pretty easy, stock REW turbos need 15ish psi, a 60-1 to4 should be more like 10. engine can be stock, and as long as its tuned ok, will be fine for years.



NON turbo, you need to do a pretty radical port, either a big bridge or peripheral. its like putting a giant cam into the thing, so it can be grumpy. power will be in the 5000-9000+ range, depending on porting, and intake and exhaust tuning. you need aftermarket or custom intake manifold. different ecu or a carb. exhaust must be really free flowing, and this is hard to keep quiet.



numnber 2 sounds more like what you're looking for, it is more involved, there is a time proven road race type setup, but its LOUD



plan C might be to get an REW core, pull the turbo off and run it NA, be 180ish hp, be fun in a light car


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