Mazda Rotary Club

Cars by Model Type => 3rd generation RX-7's => Topic started by: gmonsen on April 23, 2011, 01:06:21 AM

Title: Finishing NA 20b engine bay remake
Post by: gmonsen on April 23, 2011, 01:06:21 AM
I am close to done with the engine bay re-do.  Only thing not done ois the intake piping.  What you see here is temporary.  I am putting in a new -- narrower, but thicker -- radiator that will allow the intake to breathe directly from the grille opening.  The only other thing left s the new dual exhaust in the bumper.

Gordon

(http://i234.photobucket.com/albums/ee255/gmonsen/Mazda%20Rx7/Motor%20Photos/Engine%20bay%20cleanup/DSCN2492.jpg)

The coils are much better laid out...
(http://i234.photobucket.com/albums/ee255/gmonsen/Mazda%20Rx7/Motor%20Photos/Engine%20bay%20cleanup/DSCN0631.jpg)
(http://i234.photobucket.com/albums/ee255/gmonsen/Mazda%20Rx7/Motor%20Photos/Engine%20bay%20cleanup/DSCN0617.jpg)

I hid all the fuses and relays and everything else I took off the driver\'s side fender well and put it under this cooling shroud over the radiator.
(http://i234.photobucket.com/albums/ee255/gmonsen/Mazda%20Rx7/Motor%20Photos/Engine%20bay%20cleanup/DSCN0629.jpg)

Few other things like covering the interior and exterior door handles in black leather.  You don\'t notice it, but feel it when you touch.
(http://i234.photobucket.com/albums/ee255/gmonsen/Mazda%20Rx7/Motor%20Photos/Engine%20bay%20cleanup/DSCN0602.jpg)
Title: Finishing NA 20b engine bay remake
Post by: gmonsen on April 23, 2011, 01:13:33 AM
Here are a few videos of my car on the dyno just before I cleaned up the engine bay.  (NOT my camera.  Maybe the Green Hornet took the videos, but they put them on youtube anyway.)

Gordon

http://www.youtube.com/watch?v=Q0DBQQVPlzU

http://www.youtube.com/watch?v=ceOeVw6wWz0&NR=1

http://www.youtube.com/watch?v=NX-vq3Vd5bg&feature=related
Title: Finishing NA 20b engine bay remake
Post by: goldk28611 on April 23, 2011, 01:33:52 AM
looking good! me likes! :D
Title: Finishing NA 20b engine bay remake
Post by: Mir on April 23, 2011, 02:27:57 AM
Nice NA 20B, Can you tell me, what coils were you running?? I am a bit lost with coils..

Syed
Title: Finishing NA 20b engine bay remake
Post by: re japi on April 23, 2011, 05:58:07 AM
I´m jealous, i want NA 20b too... =D
Title: Finishing NA 20b engine bay remake
Post by: B.Martin on April 23, 2011, 07:48:27 AM
Pics looks great, got to love the 20b!
Title: Finishing NA 20b engine bay remake
Post by: SiH on April 23, 2011, 08:19:55 AM
That intake makes me go all weak at the knees...
Title: Finishing NA 20b engine bay remake
Post by: Brett on April 23, 2011, 09:27:21 AM
Very nice build :)

What size ports are you running?
Title: Finishing NA 20b engine bay remake
Post by: gmonsen on April 23, 2011, 10:31:08 AM
goldk28611...  Thanks.

Mir...  They are Bosch, but I can\'t remember the model number.  Will check later today and post up.

re japi...  The NA 20b is phenomenal.  Great power and no worries.  Very reliable.  (I\'ve been 29b since 2006.)

BenRx...  Got to...

SiH...  Yeah.  It is not only beautiful, but added 29 whp all by itself.  I designed and built it and had it ceramic coated.  The intake piping will eventually be the same ceramic color coating.

Brett...  If by size you mean the actual dimensions, I don\'t know.  Never actually measured them.  They are close to a down half bridge.  Kind of as big an "extend" port as you can go.  The idle is fairly stable at 950 rpm with just a bit of that lopey idle that 20b big ported motors have.


I really like how empty the engine bay is now even compared to a 13b twin or single.  And, let me tell you that before I did this 5 years ago, people were saying that the 20b would be heavier than the 13bt\'s etc.  Not true at all.  No intercooler, no turbo (s), no downpipe, and no IC hard pipes mean its actually about 100 pounds lighter in the front.  Weight distribution is now exactly 50-40 and soon 49-51.  (Stock is 51-49)

Gordon
Title: Finishing NA 20b engine bay remake
Post by: gmonsen on April 23, 2011, 10:52:48 AM
Here\'s a photoshopped version of what the intake will look like.  However, tha hard pipe will go straight down under the cooling shroud.  No filter.  I\'ll try to do one that\'s a bit better than this and post later.

Gordon

(http://i234.photobucket.com/albums/ee255/gmonsen/Mazda%20Rx7/Motor%20Photos/Engine%20bay%20cleanup/gmon_white.jpg)
Title: Finishing NA 20b engine bay remake
Post by: Mir on April 23, 2011, 11:04:18 AM
I m goin through researching on coils-For my next project. Would like to know abt Bosch coils too!! Coz I m serious abt MSD DIS 4 (ho) and DIS 2 (ho) ignition system with MSd coils.. Any info on dat subject will b appreciated!! Syed
Title: Finishing NA 20b engine bay remake
Post by: gmonsen on April 23, 2011, 11:18:56 AM
My old 13b single turbo used an MSD DIS-2 on the leadings and a 6a on the trailings with MSD Blasters for coils.  It was a bit of a pain to set up, but worked great and I loved it.  However, many people over here have had issues with the MSD\'s.  I never did, but several tuner shops don\'t like them here.  I think it was more a customer service issue, but don\'t know for sure.  I may eventually try an MSD setup on the 20b, because the motor spins to 10,000 rpm.  I think there should be a benefit from the more accurate digital firing at high rpm.  The capacitive discharge effect up to 3000 rpm of the MSD\'s might be of some marginal value as well, but not much, I think.

The stock Mazda coils are really very good, but I have seen some of them turn to goo from overheating over an extended period.  New Mazda coils are quite good.  However, the MSD coils have faster rise times, so they run cooler, and of course, they have a higher output.

I am thinking about going with a third plug per rotor like the 26b\'s have and might try the Denso coil-on-plug setup.

Gordon
Title: Finishing NA 20b engine bay remake
Post by: Mir on April 23, 2011, 11:32:06 AM
Cheers for ur info, I wud like to give u a bit of info on my car, i m running single turbo 20b fd, I was running after market coils but didn\'t like them, so for a time being went bk to stock 3 rotor cosmo coils!! They work great but I guess with all dat premixing business with microtec ecu, plugs gets flooded often coz of lesser stronger spark than need ( I think). Now I bought Motec ECU, which can run 3 and 4 rotor engines.. I m in a Seriously thinking Mode.. So if u cud assist further on ignition and coils matter, I wud really appreciate dat!

Syed
Title: Finishing NA 20b engine bay remake
Post by: gmonsen on April 23, 2011, 12:40:23 PM
Syed...  Neither the coils nor the ecu would cause the plugs to flood from a mechanical or electrical issue.  What are your air fuel ratios running?  If you are flooding the plugs, I would suspect some physical issue with the fuel setup.  I had a 20b single turbo for a few years while I was building my NA motor and was running a pectel ecu and stock coils.  (Could never use the power effectively and don\'t drag race.  It was useless on a road course.)  Never had any issues with flooding.

Gordon
Title: Finishing NA 20b engine bay remake
Post by: Mir on April 23, 2011, 01:01:30 PM
Quote from: gmonsen;757645Syed...  Neither the coils nor the ecu would cause the plugs to flood from a mechanical or electrical issue.  What are your air fuel ratios running?  If you are flooding the plugs, I would suspect some physical issue with the fuel setup.  I had a 20b single turbo for a few years while I was building my NA motor and was running a pectel ecu and stock coils.  (Could never use the power effectively and don\'t drag race.  It was useless on a road course.)  Never had any issues with flooding.

Gordon

Cheers for clearing this up for me. Ok when you said "I would suspect some physical issue with the fuel setup" what you actually mean? Physical issue with a fuel set up is not really ringing any bells :), or I may say, my knowledge is not really that developed to get your indication, So, if you don\'t mind explaining to me what entails physical Fuel Setup issue, I may check it out on my car.

As far the Air Fuel ratio is concerned, I recently had a rebuild done, 2 months ago, I am still running in the car as it has only done arround 846 miles on the new engine. I need to get it remapped, after it has run in, and therefore, I think, after it has been remapped, this issue of flooding will go away...

Any info, :Typing will be appreciated

Syed
Title: Finishing NA 20b engine bay remake
Post by: gmonsen on April 23, 2011, 06:26:37 PM
Syed...  I was simply wondering if the fuel pressure regulator was acting up or too much pressure under certain circumstances or whatever.  The biggest thing is that it would seem that you are adding too much fuel somewhere on your maps and that should show up in your AFR\'s.  They should be running, say, 10.5-11:1 and I suspect somewhere, like idle, you are adding too much fuel.  Since your motor is fairly fresh, the tuner may have set a very rich AFR, like 9.5:1 to be safe (at least in his mind).  If that were right, its still the wrong thing for him to have done.  Even keeping it very rich to be sure it doesn\'t detonate, mapping that rich is not at all necessary.  

I would also ask whether, when you rebuilt the engine, you put in new seals and springs?  The only real issue on break in is bedding in the seals and they should be seated by now with 800 miles on it.  Do you have a dyno sheet with the afr\'s when it left the shop?

Gordon
Title: Finishing NA 20b engine bay remake
Post by: Mir on April 23, 2011, 07:23:06 PM
Quote from: gmonsen;757698Syed...  I was simply wondering if the fuel pressure regulator was acting up or too much pressure under certain circumstances or whatever.  The biggest thing is that it would seem that you are adding too much fuel somewhere on your maps and that should show up in your AFR\'s.  They should be running, say, 10.5-11:1 and I suspect somewhere, like idle, you are adding too much fuel.  Since your motor is fairly fresh, the tuner may have set a very rich AFR, like 9.5:1 to be safe (at least in his mind).  If that were right, its still the wrong thing for him to have done.  Even keeping it very rich to be sure it doesn\'t detonate, mapping that rich is not at all necessary.  

I would also ask whether, when you rebuilt the engine, you put in new seals and springs?  The only real issue on break in is bedding in the seals and they should be seated by now with 800 miles on it.  Do you have a dyno sheet with the afr\'s when it left the shop?

Gordon

Hi Gordon
thanx for ur reply. The engine was built with brand new parts!! Including housings and the rotors clearanced on top of the rotors was done! I don\'t have exact figures of the AFR, but I can get them! My turner and builder is the top man in the UK! He has built serval triple and quad rotors! His name is Pip of WGT! Very experience man!!

Let me know, if u want more info!!

The fuel pressure regulator is showing just above 40 psi! Or little Bit above....
Title: Finishing NA 20b engine bay remake
Post by: rx7boy on April 23, 2011, 07:51:11 PM
Not from personal experience and not doubting Pips work as he is somewhat of a legend when it comes to the rotary, he does however like to map a car on the rich side from the sounds of things, hey its better than lean. Im sure once the car is run in and mapped you wont have issues with your plugs fouling up.
Title: Finishing NA 20b engine bay remake
Post by: Mir on April 23, 2011, 11:36:25 PM
Quote from: rx7boy;757714Not from personal experience and not doubting Pips work as he is somewhat of a legend when it comes to the rotary, he does however like to map a car on the rich side from the sounds of things, hey its better than lean. Im sure once the car is run in and mapped you wont have issues with your plugs fouling up.

don\'t get me wrong,Pip is a legend and in my opinion there is no one competent enough to challenge his rotary knowledge in the UK. It\'s all abt tunning when it comes to rotaries!! And in my opinion Pip has mastered that!! I m very pleased with his work.. This is with his permission that I m free to ask people questions. He knows, I love to research on the rotary, that\'s y he gets emailS from me left right and centre, and he always welcome my questions...i always inform him abt da questions I pose to the others!! So that he can c wat other thinks!! Very intelligent man.. And off course very busy!! He is mapping my motec too!!

The discussion I was having was purely enhancingy knowledge on things and getting the right set up.. Hope this explains, y I was asking questions!!

Syed