lespaul166

So I posted a thread the other day about squeezing power out of an N/A. Of course my buddy started tearing into me about how the absolute boatload of money I'm going to spend getting my N/A to 180RWHP could get me way more power on any other car ever. And I gotta be honest, Im partially worried Im gonna do all this work, get the 180RWHP, and barely notice a difference in the car, and be thousands in the hole. I seen a nice built TII for sale, and while I cant afford it right now, It got me thinking about maybe just biting the bullet and putting a turbo motor in the car. I have a turbo car right now as a DD and hate it, but I also realize that the car is just set up like pure garbage and limits boost to almost nothing in 1st and 2nd so by the time you hit 3rd all the torque is gone and the car feels dog**** slow despite the 230bhp. But before I keep thinking about it, is it even feasible to do? Or are you going to spend thousands getting a motor, intake, turbo, exhaust, wiring harness, hood, etc. and end up with just a bone stock turbo II? The Turbo II motors I see for sale are around $3000.

I would prefer to stay N/A. Would I really feel the 60 or so RWHP difference? Or am I just pretending like I'm gonna have a fun car and be disappointed?

Would the Turbo II conversion be feasible? or will I spend just as much money as making the N/A do 180, and make the same numbers, albeit with turbo lag and all the headaches that go along with a turbocharger?

Dak

Here's my take on it and my plan because I think I've had the same thoughts as you over the years. I see no reason you can't continue down your current path of stay n/a and yet swap to a turbo later on. That's my current plan. The one thing I feel that will help with that 180rwhp goal is a good standalone. I know the car in the other thread didn't use one but I think it's the way to go and it wouldn't be money wasted. From my time on here over the years I've gathered to make more power than a stock TII reliably a standalone is the way to go along with the appropriate upgrades to the fuel system. This is my plan as I want to go turbo later on but I'd like to get as close to that elusive all motor 200rwhp first. Most things I've done since my last rebuild has been with that in mind. I street ported the intake and exhaust and used TII rotor housings on that engine. I ground the inlets to my RB header in an attempt to smooth the flow into it and correct the mismatch between the exhaust port and the header. My original plan was to modify a TII lower intake per the how to on Aaron Cake's website to use it on a N/A engine. Then most of the turbo parts bolt right on like on a turbo car. Just have to figure out getting oil to and from the turbo. As for the n/a intake. I used to want ITB's but I'm not going that route now because of my turbo plans. That( not using ITB's) would've limited me on my max n/a power but I now have a plan for that. After I get a standalone I'd like to make something to adapt a 3rd gen upper intake to my n/a lower which I think will flow enough for more than 200hp. Ok, sorry if I've hijacked your thread with my wish list. The point I'm trying to make is with the right planning of your modifications it won't be money wasted if when you get to then end you decide you'd like more power than the n/a can deliver. You may be happy with 180rwhp.

You won't need a hood if you just go with a front mount intercooler from the start. You'll already have the wiring harness from your standalone install. You may just have to change some wire lengths. You won't end up with a stock TII because you'll already have half an exhaust from the n/a set up just have to rebuild the front portion. Freeing up exhaust creates more boost. Sounds like you're going to use the Walbro fuel pump so you may just have to get bigger injectors than you ran on your planned n/a setup. If you succesfully hit 180rwhp on a standalone who says you have to use the stock turbo when you switch. You'll have a standalone to control it all. Just will have to be extra careful because the margin for tuning error is slimmer with the n/a's high compression rotors. I hear 300rwp is about the safe max on them.

DC5Daniel

iTrader: (10)

It's definitely feasible, and has been covered many times on this forum and many others for decades. Point being, it's very well documented.

It used to be absolutely the most cost effective to sell the NA and buy a TII; most people didn't like hearing that, but it was the truth. Plus a lot of conversions ended up as hack jobs or hodge podges with NA transmissions/differentials. Now with even junky TIIs selling for way more than they really should be worth, you might actually come out on top doing a swap.

lespaul166

The only reason I don't want to sell the car and buy a TII is that

1) I had my steering rack professionally (and expensively) converted to manual and don't want to sell it with the car
2) Its the RX7 that I found while drunk and lost in the middle of nowhere while I wasn't even looking for a car. Buying a TII off craigslist wouldn't have that same sentimentality.
3)This shell has absolutely ZERO rust. Not even surface rust. The exhaust is flawless. Some of the thermal reactor bolts were a little brown. That's it. That's the whole reason I bought this thing in the first place and inadvertently started my downward spiral into being a rotary guy.

I thought long and hard about it, TBH I do want to stay N/A for now. I love pure power delivery and I feel like turbocharging the motor would tarnish my vision of "pure unassisted driving experience"

lespaul166

I'm going to leave it N/A for now like Dak says. I just love pure straightforward on demand power. I feel like turbocharging the car almost tarnishes my vision of "pure unassisted driving experience" Ive been going for. I work at a Lotus dealer as a Porsche tech, which really combine into what I want this car to be. Like an air cooled 911 in that you have to DRIVE the car. It doesn't help you at all. You have to be involved 100% at all times. And like a Lotus because, "Simplify, then add lightness"

As an aside, the guy im having do my machine work says theres absolutely no point to porting a 6-port unless you go peripheral, anything less and you wont see any gains. Yet ive seen a lot of N/A guys talk about street porting 6 ports. Which is the reality here?

Dak

Not to send you down some other path but I wouldn't spend $3000 on a TII motor. Since I'm spending your money and not mine I'd spend the $4000 to $5000 to get a Cosmo13B-RE or 3rd gen 13B-REW motor. Take the turbos off and run it with a standalone. The intake ports are better on them. Especially the REW. There was a guy on here that made 230rwhp with a street ported 13B-RE. All motor. That car was built by Defined Autoworks.

Granted there are install hurdles. The Re is easier. The REW requires custom mounts but there is a company or two that sells them.

Dak

I partially disagree. Not really anything to be gained from porting the aux( 5th and 6th) ports. They close way late already. There is some gain to be had from porting the primary ports and either removing the exhaust diffusers in the n/a housings or using turbo rotor housings and porting the exhaust. My car went from falling on its face above 7500rpm to pulling strong all the way to the stock ecu's 8500rpm rev limiter. Only changes were the porting, completely removing the aux port sleeves, rods and removing their bosses that stuck into the intake path and porting the header to match the exhaust ports. I don't think removing the aux ports was key. It was the street port, but I did do that so it was a difference between the two setups.

lespaul166

I need new housings for sure because the ones on my donor motor are ROACHED and I was gonna go TII housings anyways

The bummer is theres a guy near my buddy who listed a "running project" FC N/A RX7 S5 TII swap for like $4500 and its got a semi Bridgeport TII with 100 miles on it, full Megan coilovers, Koyorad, Efan, meth injection, FMIC, bigger turbo, Haltech Standalone. The body is just hairy and the interior is a mess. I just don't have the money right now (Got the rona and had to take 2 weeks off work) and by the time I did I'm sure this will be sold. Comes with everything needed to put a TII in a N/A car. On the other hand, I really enjoy staying late by myself at the shop, playing my music on the shop radio and working on the 7 til midnight. Buying a built job like that takes it away.

I've got time. I can build a TII later. Im not dying tomorrow (maybe). The 13B-RE is interesting though. Im sure those are rare as hens teeth, but If they were still around by the time I hit my milestone, I would definitely go that direction in order to maintain natural aspiration.

Dak

You can try to do like I'm doing. Buy the turbo parts as good deals come along. I picked up a blown S5 TII motor locally last fall( bad coolant seal on front rotor) from a failed TII swap.This sounds bad but I don't remember what I gave for it. $500 or $600 dollars but it was a mess. Had most of the pieces and I got the gearbox. Had a S4 throttle body and missing the boost sensor and boost control solenoid. Finally opened it up and the front iron is trashed and the center may not be usable from sitting over with coolant in it for who knows how long. Don't know yet if the rotors a salvageable. I mainly got it for the manifolds, the turbo and the gearbox, anything else is a bonus. Picked up a 3rd gen upper intake and throttle body off Ebay last month. I won't use these parts for years but I wanted to pick them up before the supply fully dries up.

As for the 13B-RE there are three of them on Ebay right now. Bad part is they are about $2000 more than a year or two ago. A couple years ago TII motors were around $1200 to $1500 and RE and REW's were about $3000.

Sideways7

iTrader: (7)

I had an NA and it was quick, but not what I would call fast. I also had a manual rack (OEM manual rack) and an upgrade pressure plate that had a very solid feel to it. It was a ton of fun and I even tracked it occasionally. I had the standard stuff - streetported S5 block (S5 rotors are higher compression). The S5 UIM nets you a little extra top end. Its pretty gutless down low with everything wired open, though, so I made up a system using solenoids, rpm switches, and a small air pump to keep them operating normally. Aftermarket air filter, open exhaust. Once you get past that, it starts costing a lot of money for smaller gains. Standalone, aftermarket intakes, custom exhaust tuning, etc. Even with all of that you will likely never see 250 WHP. So when I overheated my engine, I did a turbo swap. If you are concerned about money, it can easily become a money pit once you do that swap, though. Make sure you have clear goals and stick to them or else things can spiral out of control.

j9fd3s

iTrader: (3)

my friend had a GTUs that was really good. he bought a wrecked one with a dead engine. replace engine, car got an FC2000 body kit. Racing beat exhaust and we did Bilstein based coil overs on it. much cleaning and tweaking, it was really fun. we never put it on the scale, but it felt really light, handled (and rode) great. big fun.