An End-of-build Retrospective on my Rx7 Evo GT by gmonsen

9 minute(s) of a 144 minute read

Here's an updated picture of the rear end with the round exhaust tips. Also, the exhaust box will need to be made out of stainless or some such to handle the heat and there will need to be some insulation added around it. Anybody still like the rotor-shaped outlets? I'm going with the round anyway, as much as I love rotors...  I still have to overcome my need for symmetry, I suppose, but am thinking the outlets should be the same diameter as the 99 spec round tail lights. Looks like a good size...

1-28-2011

UPDATE SIDE VENDER VENT TREATMENT

Not much of an update. Everybody is waiting for parts or pieces of some sort to be made. Several things are close, but as we all know, it takes more time than it should.

Anyway, here are some pictures of the aluminum strakes I designed. This is one of the more controversial little projects I took on and so I want to say again that I try a lot of things and that not al of them make it. I've wasted a fair amount of time that way. 

I designed 3 aluminum strakes for each of the two side vents. However, I designed them so that I could see how 2 strakes would look or how 3 strakes would look. I haven't polished them yet or decided whether they look good, but thought I'd put up some (poorly taken coming in out of the snow) pictures. The strakes fit into the vent opening perfectly and are positively mechanically affixed.

I think I like the views with 3 strakes...

Gordon

2 Views with 3 Aluminum Vent Strakes

3 Views with 2 Aluminum Vent Strakes

1-29-2011

I've tried many different treatments of the side vents, because, as you know, I do look for opportunities to add detailing that is suited to the design and doesn't go over the top. Of all the things I've tried, this has been the most difficult and most problematic. I am still not at all sure whether anything relating to the vents can be done that works for me. I'm still not sure on the strakes. I have only seen the pictures I posted and really need to see "the whole thing" before I will know what I think. If I don't like them, I have one or two other designs I've shown before (pasted below again) that I will try. I may end up doing nothing in the end. Or, I may like the strakes yet. I think one of the problems is that the vents are iconic to me. As designed originally, as I said earlier, its such an organic thing even though its mostly we owners that appreciate it fully. (Maybe a chrome mesh in there instead of the black plastic piece that everyone breaks or loses? What about an exact replacement for that piece out of aluminum or stainless which might shone more in there?) Anyway, I am hoping for a few more pictures from the front three quarters in particular. (I won't post those up, though...)

The last things cosmetically are really something here (maybe) and the rear bumper exhaust outlets. I am doing these while we wait for engine pieces to finish the rebuild. If I hadn't changed the intake setup and added Logan's new headers (which he honestly believes add 30 whp), it would be done... So I might as well play with it now, since when the motor's done, its done until after Deal's Gap. 

Gordon

This was the other major design theme I was pursuing. The problem is that you have to modify the vent insert and probably modify the actual fender there just a bit to make it look like the photoshop version below. If I tried this, I would just take out the vent piece entirely and cut away to of the fender behind it and put slat type vents like in the last sketch above that shows the side view.

Here is an overview of the stainless steel plenum or box that shows how it sits in the middle of the aluminum bumper crossmember. The plenum will be welded to the two side pieces that remain of the crossmember after the middle is cut out. The crossmember becomes a heat sink. DEI fabric will cover the inside of the bumper shell and there will be abundant insulation added all round.

This view shows the rounded shape...

Again, nothing is to scale, or exact, but here's how the exhaust pipe gets into the exhaust plenum.

2-1-2011

Phil... I agree entirely. However, I have tried a number of things that haven't worked and am thinking of just backing off it for now and come back with fresh eyes. What I have tried to do on every design so far is to have whatever I do fit with the existing vents and opening and the indentations on the door. What I am going to try next is to assume the vent piece is out and that I can cut away fender from the opening back to the door, if necessary. This opens up a lot of possibilities.

I also am getting closer on the motor. Te two things I've been waiting for are a new set of headers from Logan at Defined Autoworks and a new intake plenum and runners that I designed and that I am having made. The headers are quite a bit longer (1.5 feet plus) than my current headers, which should increase top end power by about (Logan's guess) 20 ft lbs. I think my intake plenum and runners will also increase power by a good deal, but I have no way of knowing how much. However, the plenum has more than twice the air volume from stock and the runners are longer and have notable taper to them for velocity. They are also a bit larger than stock in diameter over the length. Finally, they will be welded to the lower intake manifold cut off just after the (really bright) 90 degree turn into the port. The runners themselves are much better as they hit the sawed off LIM than stock as well, since the stock runners have to negotiate other parts attached to the engine. 

The headers, plenum and runners should all be done by this coming weekend, so the engine goes back together next week! 

Gordon

Here's an individual runner, showing the taper...

Here you see the flange for the 90mm throttle body.

Here you can see just how much larger the new plenum is compared to the stock 20b plenum. (When you're forcing air in, you don't care too much about flow...

I thought I would post a few more of the intake plenum and runners. They are starting to take shape here. Just 3 more to go tonight!

Gordon