1988 "20B"/13b... TII

[fidelity101]

ooohhhh I like the duct work.

[toplessFC3Sman]

I know it may sound like sacrilege, but you might want to consider punching a couple vents in the undertray so that any possible leaks or water that runs under the hood has a place to drain. Definitely do it behind the radiator, IC & oil cooler so that you don't allow the pressure there to escape tho.

The fab work looks very nice, and everything seems to fit well.  Did you have use of a sheetmetal brake, or did you do it with a couple 2x4's and clamps?  Either way, it came out well man!

[fidelity101]

I know it may sound like sacrilege, but you might want to consider punching a couple vents in the undertray so that any possible leaks or water that runs under the hood has a place to drain. Definitely do it behind the radiator, IC & oil cooler so that you don't allow the pressure there to escape tho.

The fab work looks very nice, and everything seems to fit well.  Did you have use of a sheetmetal brake, or did you do it with a couple 2x4's and clamps?  Either way, it came out well man!

screw that! just make sure the top side is super polished and accelerate and it will all drain out the back! lol.

[ITSWILL]

I know it may sound like sacrilege, but you might want to consider punching a couple vents in the undertray so that any possible leaks or water that runs under the hood has a place to drain. Definitely do it behind the radiator, IC & oil cooler so that you don't allow the pressure there to escape tho.

The fab work looks very nice, and everything seems to fit well.  Did you have use of a sheetmetal brake, or did you do it with a couple 2x4's and clamps?  Either way, it came out well man!

Yeah, a couple holes might be a good idea. The sides were bent up with a brake and the rest was bent with a piece of angle iron and C clamps.

[ITSWILL]

Well I drove over an hour to Andrews house to put her up for the winter. Everything went pretty well until it died and wouldn't start right in front of his house. Lucky me, we just pushed it in the rest of the way.  I'll have to check the logs and see what happened. One way or another it was a fun drive. I also want to say thanks to Topless for all the help with the tuning so far.

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[~Groll69~]

It was a beautiful day for the drive down there.  I am glad the car died right in front of Andrews house and not a few miles away.  That made it getting it to its winter home that much easier.

[ITSWILL]

Today I was thinking about that drive to Andrew's house in the video.  I found myself driving my LS1 car down the same roads, but making sweet open wastegate 20B sounds...  I think I really need to get back to this project.

[Senketsu]

Get it up and running again! I lost the video I had of wonderful 20b burnouts and I need another!

[ITSWILL]

I am finally getting back to this project.  Unfortunately the 20B is not going back into the car.  But on the positive side I am taking on a new engine configuration that should Be a lot of fun as well as a great learning experience.

I will be replacing the 20b with a Carbureted S4 6 port 13b.  The engine will be a semi-bridge port with the primary throttle blades of the carburetor feeding street ported primary ports. The Carburetor secondaries will feed the bridge-ported secondaries and Aux ports.

The ignition will consist of a distributor with an MSD box and FC coils.

I am hoping for about 200 whp and am considering up to a 100 shot of nitrous.

Thanks to Dondo, I have a donor engine to work with.  The engine had no compression on any face.  What Marcus and I found is that all the seals were stuck everywhere.  The rotors have been sitting in gasoline for a couple weeks now and will hopefully let go of the side seals soon!

Additionally the front rotor housing had major wear down the center and the front iron was blown out between the exhaust chamber and the coolant passages.

I will be making my own exhaust header that extends to about the rear axel before merging.  Similar to what is described here. You are not allowed to view links. Register or Login

As this project continues I am going to try to list all the technical resources I use and find most relevant.  It seems there is a lot of hearsay when it comes to building a solid NA engine and I would like to help sort through some of that. 

This build will be focused around a roughly $500 budget which should make it interesting. I want to keep it cheap well because I don't want to spend a lot of money as is common with a lot of RX7 guys especially ones working on NA engines.


As for the 20B I have big plans for that down the road...

[murz]

This will be a fun project for sure! I'd be happy if we made 200whp, though I know people make over 200whp with no porting on the 6-port engines somehow. I feel it should be bridge ported as well, and see what can be done.

From what I've read it's advised to not bridge the auxiliary ports (This seems to be due to the fact that the 6-port closes super late already).

I think the header will benefit from long runners, that will be cool to create too. I think some of this will be good experience for the LS car as well.

[ITSWILL]

I just ordered an O-ring kit from Atkins.  Before I did I thought I had to do some research since the replacement front Iron I got was for an S5. Turns out their kit covers 86 though 92 and comes with the extra o-ring for S5.

Anyhow I found this write up that describes the differences in front Irons that I am talking about.

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Now I guess I have to start cleaning parts...

[ITSWILL]

This will be a fun project for sure! I'd be happy if we made 200whp, though I know people make over 200whp with no porting on the 6-port engines somehow. I feel it should be bridge ported as well, and see what can be done.

From what I've read it's advised to not bridge the auxiliary ports (This seems to be due to the fact that the 6-port closes super late already).

I think the header will benefit from long runners, that will be cool to create too. I think some of this will be good experience for the LS car as well.

The simulator I ran seemed to think it would want to close at 60 degrees ABDC. Like you said it closes pretty late at 80 degrees.  Since the bridge is what becomes your opening point I think it is still worthwhile to bridge port the aux port such that you get more area at the opening point but only take it so far up that the bridge closes at around 60 degrees

[ITSWILL]

Just for comparison this is the timing on the Renesis

[murz]

I gotcha, so you're thinking of a partial Aux bridge sort of, which doesn't close any later.

[ITSWILL]

Correct,

I'm still looking for a good NA housing if anyone has one.