Need Input! Rotary Budget Build!

[Captain KRM P5]

this was the list i had come up with thus far; any input/advice is welcome of course

Engine Reinforcement Beam for 13B<o =""></o>

http://racingbeat.com/resultset.asp?PartNumber=11832

Price: $85<o =""></o>

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Oil Pan from GSL-SE<o =""></o>

http://racingbeat.com/resultset.asp?PartNumber=11831

Price: $82<o =""></o>

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Hardened Driveshaft Yoke<o =""></o>

http://racingbeat.com/resultset.asp?PartNumber=12031

Price: $65<o =""></o>>

Japanese Spec 13B Rotary Engine with Turbocharger and Intercooler<o =""></o>

http://www.jspecautosports.com/catalog_product.aspx?prod_id=70

Price: $1000<o =""></o>

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1988 Turbo II RX7 ECU, Wiring Harness and Knock Sensor<o =""></o>
from eBay or Mazda dealer

 

[JDuncan]

Might wanna go with a different year than 88. That is the year that they transitioned from low impedance injectors to high impedance. It happened mid year. If you are gonna go that route, then make sure you research it well and watch closely what you are buying. i would probably go with a standalone and new harness. It adds a grand to your budget, but makes the car ultimately more upgradeable in the future. The number one hurdle to overcome in rotary performance after the exhaust is fuel, and a standalone is the easiest way to jump clear over it.

 

[Captain KRM P5]

Might wanna go with a different year than 88. That is the year that they transitioned from low impedance injectors to high impedance. It happened mid year. If you are gonna go that route, then make sure you research it well and watch closely what you are buying. i would probably go with a standalone and new harness. It adds a grand to your budget, but makes the car ultimately more upgradeable in the future. The number one hurdle to overcome in rotary performance after the exhaust is fuel, and a standalone is the easiest way to jump clear over it.

thanks for the info. i'm not looking to spend much more money (getting married in a year) so the standalone is out, even though I like haltechs and i know they work well on the rotary route. the reason I was looking more at an 88 is that I heard they had better knock sensors, etc than the prior years.

i am looking, due to budget constraints, to keep the old transmission. a new clutch, flywheel, and throwout bearing would be on the list, and i know the trans bolts up without a hitch. However, how would the clutch/flywheel work out? My brother and I think that the flywheel and pressure plate from a 13b would be used with the disc from a 12a. thoughts?

 

[Lt. Dan]

I'd vote for keeping it red, but I'd spice it up a little bit by purchasing some silver flake to mix in.... That would look hot.... Good luck with the first gen project, I love mine!

Dan

 

[JDuncan]

I don't know how well the stock trans in that car will handle that kind of power change. I had to replace it once due to it snapping the output shaft into two pieces and that was just with the 12a and the dual webers. The GSLSE rear end in the car should be good to around 200 hp with abuse and a bit more if driven right. The tranny is definitely the week side though.

 

[Captain KRM P5]

I don't know how well the stock trans in that car will handle that kind of power change. I had to replace it once due to it snapping the output shaft into two pieces and that was just with the 12a and the dual webers. The GSLSE rear end in the car should be good to around 200 hp with abuse and a bit more if driven right. The tranny is definitely the week side though.

could it be possible that the output shaft was snapped becuase of age/wear? I agree that I am hesitant to keep the old tranny. I'm going to call a few rotary chums tomorrow (racing beat, mazdatrix, et al) and see what thier over all opinion is. Swapping in the new tranny would require a custom made driveshaft. Any one have a clue what a custom drive shaft would run? If its not too much, I would really consider it but I see that as being a pretty costly piece of material

 

[Captain KRM P5]

another question, for those in the rotary community - how much would a pair of Weber carbs along with the intake manifold fetch $wise?

 

[Rotaryrocket]

rocket, what did you mean by 'formula mazda'. kinda lost me on that. to kind of revive this thread, i dropped the car off at my friend's house where we'll soon begin tearing into the car and stripping the paint, etc. this was the engine I was thinking of putting into it;

http://www.jspecautosports.com/catalog_product.aspx?prod_id=70

Hey Cap. I was referring to a Formula Mazda open wheel race car, because of the weight you mentioned. Being that if you stripped a first gen and caged it the lightest you'd probably get would be 2100 lbs. with driver. So simply put I was being sarcastic, and meant no disrespect. Also, I have a friend that owns a mazda repair shop and specializes in rotary engines. He has intakes for 48 IDA Weber carbs (his own castings). He is an avid road course racer in the numerous RX-7 and Miata classes in the Northwest region sanctioned by the IRDC and SCCA. I have been reading your questions on this thread and have wanted to respond, but, to be honest, I'd be asking him first to get you the right answer. No sense in pretending I know everything about these cars....so here is his web site: http://mazdamanor.com/ If you should have problems getting a response from his site, it is possible that it is still under construction. But everything you have asked, he has the answer for, believe me...Hope this is helpful...and good luck on your project!! Also just for s**** and giggles, I am starting to build a site for my rotary projects, only have a few pictures up there right now, but you can still take a look...http://rotaryrocket.maclem.com/ (cool)

 

[Rotaryrocket]

I don't know how well the stock trans in that car will handle that kind of power change. I had to replace it once due to it snapping the output shaft into two pieces and that was just with the 12a and the dual webers. The GSLSE rear end in the car should be good to around 200 hp with abuse and a bit more if driven right. The tranny is definitely the week side though.

Completely true....the transmission is the weakest point in an Rx-7. But the stock tranny will handle a peri port 12A (approx 275 H.P.). Dont get me wrong, it will have to come apart often for repair, but if it can last an 8 hr. enduro (thats 8 hrs. @ 6000-10000 RPM) I wouldnt really worry too much about it. Besides, my street ported '82 (which I constantly run to 9500) is still in working order after 2 yrs. (cool)

 

[Captain KRM P5]

After talking in great detail with Racing Beat today, I am leaning towards going the street port route. Question is, they 'sell' both intake and exhaust porting services. Would I need to buy both to get the most out of that engine?

 

[supa saiyan pr5]

Captain KRM P5...have you ever thought of just getting a 12a turbo engine ...rebuild it and port it .. you'll be able to keep the stock tranny, driveshaft and some other components....I have a friend that had the 12AT in his 83 gsl and it ran sweet.....you'll need the 85gsl-se computer to controll the injectors on the 12AT...If 250hp is all you want then I think you should consider the 12AT.....



Jeremy

 

[Rotaryrocket]

After talking in great detail with Racing Beat today, I am leaning towards going the street port route. Question is, they 'sell' both intake and exhaust porting services. Would I need to buy both to get the most out of that engine?

Yep...you want both done Cap. It costs more in the begining to build the motor right, using new or near new parts, but its worth it in the long run. If you're building a motor, I'd recommend sending your rotating ass'y to be balanced at Mazdatrix also. This will help with the H.P. and give you more confidence that things wont fly apart at the upper RPM's.

 

[Captain KRM P5]

Captain KRM P5...have you ever thought of just getting a 12a turbo engine ...rebuild it and port it .. you'll be able to keep the stock tranny, driveshaft and some other components....I have a friend that had the 12AT in his 83 gsl and it ran sweet.....you'll need the 85gsl-se computer to controll the injectors on the 12AT...If 250hp is all you want then I think you should consider the 12AT.....



Jeremy

i assume you would need the jspec ecu to do this? I have also been advised by Corksport that these engines were not the best way to go.

Yep...you want both done Cap. It costs more in the begining to build the motor right, using new or near new parts, but its worth it in the long run. If you're building a motor, I'd recommend sending your rotating ass'y to be balanced at Mazdatrix also. This will help with the H.P. and give you more confidence that things wont fly apart at the upper RPM's.

define 'new' or 'near new' and which parts? how much does having the rotating assembly balanced cost?

 

[Lt. Dan]

The 12at SUCKS.... to make ANY power, you have to open up the ports... they're smaller than a stock 12a....

Dan

 

[Captain KRM P5]

Dan, you look like the person to talk to about this

For a street port, what 'new' parts does one need to acquire? I have the RB header and the direct fire ignition on the car, as well as the GSL SE lim slip rear axle. With both sides ported, a lightwieght steel flywheel and thier $770 Holley setup what kind of power am I looking at?

Any input you've got is warmly welcomed

 

[supa saiyan pr5]

i assume you would need the jspec ecu to do this? I have also been advised by Corksport that these engines were not the best way to go.

You would need the gsl-se ECU....I've seen them run in MOROSO before I moved here in MA.....

LT.DAN. the engine was ported...and it ran great....suprised alot of people when he opened the engine bay....

I dont know why they would say that about the engine...its a more direct replacement than the 13b..and it still retains the 50/50 weight ratio and less headache than trying to stick a 13b in there...


But anyways..if you do get the 13 b and want to port it...I have a porting template from JUDGE ITO on the RX7 forum......


Jeremy

 

[Rotaryrocket]

i assume you would need the jspec ecu to do this? I have also been advised by Corksport that these engines were not the best way to go.


define 'new' or 'near new' and which parts? how much does having the rotating assembly balanced cost?

Well 'New' means 'New' and like new is very good used parts that have been cleaned, inspected, and tolerances checked to be within Mazdas rebuild specs. Having your ass'y balanced is cheap, $190 plus shipping.

 

[Captain KRM P5]

Well 'New' means 'New' and like new is very good used parts that have been cleaned, inspected, and tolerances checked to be within Mazdas rebuild specs. Having your ass'y balanced is cheap, $190 plus shipping.

ok cool, but which parts are we talking here? housings?

You would need the gsl-se ECU....I've seen them run in MOROSO before I moved here in MA.....

LT.DAN. the engine was ported...and it ran great....suprised alot of people when he opened the engine bay....

I dont know why they would say that about the engine...its a more direct replacement than the 13b..and it still retains the 50/50 weight ratio and less headache than trying to stick a 13b in there...


But anyways..if you do get the 13 b and want to port it...I have a porting template from JUDGE ITO on the RX7 forum......


Jeremy

how would the gsl se ECU know how much fuel to add under boost for a 12A? i thought the 85 gsl se rx7s with fuel injection were 13B?

 

[FC3s Boy]

ken how much money are you looking do drop into this project?

 

[Captain KRM P5]

ken how much money are you looking do drop into this project?

depends...i know whichever route i go it will at least cost me $2500. the paint i am getting done for free.

whats on your mind chris?