Car is 1988 Rx-7 n/a. In '88 they are rated at 146 at the flywheel. 172rwhp is about 50rwhp over stock, as a good running N/A of this year will be somewhere in the low to mid 120's.... a Turbo II of the same year usually puts down in the 150s or 160s.


Relevant mods:

Engine:

- Street ported (RacingBeat template) Series 4 motor , Turbo II intermediate housing, Rotary Aviation seals, timing advanced

Intake:

- K&N cone filter with cold air box, ported intake manifold and TB mod, Pineapple Racing port sleeves, auxilary ports wired open

Exhaust:

- RacingBeat collected header, straight mid-pipe,
2.5" RacingBeat dual exhaust

Fuel upgrades:

- 3rd gen fuel pump, 550cc secondary injectors, Apex'i SAFC


Previous owner, a good friend of mine, built the engine. Power-wise since I've had it I've done the fuel pump, injectors, cold air box, the current exhaust system, and dyno tuned the ignition timing.


Notes on the dyno graph:

1. The first pull was taken back in July when my car was really running like shit and I just didn't realize it. Auxilary ports were stuck closed (rotary equivalent of not hitting VTEC). I had a resonator and a cat in to help quiet down my old hellishly loud N1 exhaust system. I had leaky injectors and fouled plugs, so major ignition breakup.

2. The second pull was the same day, but as you can see, wiring open the ports gave me about 20 more horsepower and shifted the torque curve greatly.

3. Today's pull was with clean injectors, new plugs and wires, Racingbeat catback, and a straight midpipe replacing the resonator and the cat. Notice how uncorking all that bullshit from the exhaust gave me about 20 more lb/ft of torque. This third time the pulls were done in 3rd as was recommended by someone on the 7 forums.

I know it's not really that impressive numbers, but I'm pretty happy with it. An Rx-8 will dyno in the 170s to 180s depending on how well broken-in they are, and that's with a much more efficient manifold and higher compression rotors than my oldschool 13B.

[Edited on December 5, 2005 at 8:42 PM. Reason : .]

12/5/2005 8:31:54 PM

I NEED MORE NOS MORE NOS

that's cool good job.

12/5/2005 8:44:07 PM

172rhp.....i'm shaking, but that was a huge improvement for having that little

12/5/2005 10:15:51 PM

Not to rain on your parade but I layed this down this weekend through a unlocked 4k rpm tq converter.


[Edited on December 5, 2005 at 10:20 PM. Reason : ]

[Edited on December 5, 2005 at 10:35 PM. Reason : stupid we todd]

12/5/2005 10:20:10 PM

I really like CAM. The guy seems to know his shit. Makes me really regret taking my car to Eurospeed a year ago... good thing they went out of business.

12/5/2005 10:33:12 PM

yeh another eurospeed horror story imagine that.

12/5/2005 10:35:46 PM

Jeff at CAM told me that those dynapack dynos can be pretty accurate, but they must be operated correctly. They use hydraulic fluid that can have varying temperatures, etc. which can be tricky to calibrate I guess. So basically that asshole owner guy, in addition to being a prick, didn't know wtf he was doing.

Apparently, some guy brought 3 vipers to Eurospeed: one stock, one with a few mods, and one heavily modded. They all put down almost the same numbers on their dyno, within a couple horsepower. Then he brought them to CAM and they put down like low 400s, high 400s, and mid 500s respectively.

12/5/2005 10:45:42 PM

Quote :

"Not to rain on your parade but I layed this down this weekend through a unlocked 4k rpm tq converter."

not to rain on your parade, but alot of cars can do that with an "unlocked 4k rpm tq converter"



[Edited on December 5, 2005 at 10:47 PM. Reason : ]

12/5/2005 10:46:06 PM

Never said they couldnt. What do you make? show me another car on this board making 550whp with a unlocked converter that big

[Edited on December 5, 2005 at 10:53 PM. Reason : ]

12/5/2005 10:51:05 PM

Quote :

"Apparently, some guy brought 3 vipers to Eurospeed: one stock, one with a few mods, and one heavily modded. They all put down almost the same numbers on their dyno, within a couple horsepower. Then he brought them to CAM and they put down like low 400s, high 400s, and mid 500s respectively. "

explains why alot of m3's dynod so close up there.

12/5/2005 10:57:22 PM

hmm I think now that my timing is too far advanced, which is why I'm still getting a bit of breakup up top even with new plugs and wires. When I took it to Eurospeed it was fine, and the last time I took it to CAM I thought it was just the plugs.

12/5/2005 11:04:43 PM

Im going to have to say if you are breaking up its prolly due to timing, your afr's dont look rich enough to foul out plugs.

12/5/2005 11:09:23 PM

yeah I just talked to my friend who put the engine together. He's gonna help me set the timing next time he's in town. When we went to Eurospeed last year it had been set too far advanced as well, and retarding it gave about three to the wheels. I never had any breakup though at that time.

I'll probably just set it back to stock.

12/5/2005 11:23:06 PM

why does it say you have -199 hp?

12/5/2005 11:40:33 PM

^ The third run wasn't made?

12/5/2005 11:43:34 PM

the third run was me spinning the dyno, I think I spun a little on the second also. That picture is kinda blurry I made 550 on my first pass. This was with 4 straps holding it down on the back.

[Edited on December 6, 2005 at 12:07 AM. Reason : ]

[Edited on December 6, 2005 at 12:08 AM. Reason : ]

12/6/2005 12:05:49 AM

you niggers and your HP/TERK #'s

12/6/2005 12:06:36 AM

Quote :

"Never said they couldnt. What do you make? show me another car on this board making 550whp with a unlocked converter that big"

Probably not anyone who hasn't had a Viper handed to them from mommy and daddy, but does that mean you deserve a prize?

No.


Go fuck yourself.

12/6/2005 12:12:31 AM

Quote :

"I'll probably just set it back to stock."

Good idea. From what I understand, they are very insensitive to both timing changes and octane. Have two friends who race ITA/IT7...on 87 octane.

Quote :

"Im going to have to say if you are breaking up its prolly due to timing, your afr's dont look rich enough to foul out plugs."

For damn sure...if anything you can stand to rich up a little, I think.

12/6/2005 12:17:08 AM

I sold the viper and made my parents money on it, but go ahead please keep trying. I work 70 hours a week so shut the fuck up. Hi my names Ronny I'm poor. Do you hear the violin in the background? I do. Jealousy is women driven, but some men are bitch made.

[Edited on December 6, 2005 at 12:19 AM. Reason : ]

12/6/2005 12:18:12 AM

Ronny, he also has a supra and had an m3.

12/6/2005 12:19:40 AM

and a sti, 996 911, and about 4 different trucks. My friend has a lambo, h1 hummer, 8 different jeeps, viper gts and a powerstroke but you dont hear me crying about it.

12/6/2005 12:21:19 AM

You can get a tiny bit more power from advancing the timing in some cases, and my friend and I had it set fine a year ago when we messed with it at Eurospeed. We had no breakup then and it was advanced, and we measured a 3whp gain if I remember correctly. Obviously things have changed. Yes I'm running 87 octane.

As far as the AFR's go, the guy at CAM told me that his wideband tends to read a little lean. I am definately having a problem getting fuel up top though. I upgraded my injectors in an attempt to solve the problem, so now I'm thinking it's either a fuel pressure problem or the stock ECU is just being a bitch.

12/6/2005 12:21:51 AM

Quote :

"the stock ECU is just being a bitch. "

That might be my opinion.

12/6/2005 12:23:32 AM

Quote :

"Yes I'm running 87 octane. "

Try some good gas, if the timing is that advanced you probally need atleast 93

12/6/2005 12:26:16 AM

anything but 87 is bad for an N/A 7, believe it or not. Rx-8's require 93 only for emissions purposes... they have significantly higher compression than my car but should be fine on 89 and possibly 87. According to the rx7club.com guys it's not the ECU letting it get that lean. It's likely a fuel pressure problem or my fuel pump isn't getting enough voltage due to shitty 17 year old wiring.

[Edited on December 6, 2005 at 12:39 AM. Reason : .]

12/6/2005 12:37:42 AM

^ How does that work? 93 is bad for your car?

12/6/2005 12:39:28 AM

Thats crazy I never knew that. I know a little about turbo rotaries but not much.

12/6/2005 12:40:10 AM

I know on one of my jetski's ppl on the forums kept telling me not to run 93 octane in it at stock compression for some reason, said it would run better on 87... I'm still not real sure of the logic behind it but whatever, they were pretty hardcore about it so I listened to them

12/6/2005 12:42:38 AM

Not saying it isn't possible. Just never really heard that before.

12/6/2005 12:47:10 AM

I've heard several explanations about the octane thing. I'm not sure which is/are the most valid.

1) It's designed for 87 and burns most efficiently that way

2) Nonturbos are very resistant to detonation, believe it or not, so higher octane is a pointless waste of money.

3) Higher octane will lead to more carbon buildup

Personally, I've never heard of anyone heavily detonating a nonturbo w/o nitrous or really fucked up timing. Some people run 85 octane.

[Edited on December 6, 2005 at 12:54 AM. Reason : .]

12/6/2005 12:53:31 AM

High octane burns too slow. Hell, the flame front already has a lot of area to propagate across...especially with the neck in the rotor housing between leading and trailing plugs...

Basically, the fuel is still burning as the exhaust port is uncovered, so you end up wasting a lot of energy.

[Edited on December 6, 2005 at 12:54 AM. Reason : more info...]

12/6/2005 12:54:19 AM

I think the Renesis motor has 3 sets of plugs for better flame propogation actually

EDIT: I think they have 3 sets of injectors and still two sets of plugs. Mazda's race motors like the 4 rotor in the Lemans win used 3 sets of plugs.

[Edited on December 6, 2005 at 1:01 AM. Reason : plugs]

12/6/2005 12:55:51 AM

^^ makes a lot of sense then for a 2-stroke jetski engine like i was talking about earlier... 10K rpm's and firing on every stroke sure as hell doesn't give much time for the fuel to burn

12/6/2005 12:57:33 AM

awesome gains, congrats

i assume it's a dynojet dyno? let us know what it hits in 1/4mile whenever you find out

12/6/2005 12:57:53 AM

I've got no plans to take it to the strip anytime soon. Last time I went, I busted my differential and never got a clean run. The previous owner ran a 9.7 in the 1/8th.

12/6/2005 1:03:03 AM

I might back it down on the mr-2. Always been sticking in 93, because I figured what the hell for the $1.60 a tank. End up spending way more money on not bringing in my lunch to work.

[Edited on December 6, 2005 at 1:35 AM. Reason : .]

12/6/2005 1:08:53 AM

Save your cash and throw 87 in the Mister Two. It'll do just fine with it.

If it doesn't, retard the timing a few degrees.

The Teg gets nothing but 87, and the mileage gets shittier on the higher stuff. I just turn the distributor to run on the cheap shit...and I get good mileage to boot.

12/6/2005 1:11:51 AM

The jet-ski probably has a compression ratio on the order of 5 or 6:1 if it's a two stroke. No need for anything more than regular 87 octane. A common myth is that higher octane fuels burn slower. This isn't true. They are more resistant to knock, meaning their self-ignition temperature is higher than lower octane fuels, but the flame speed is actually higher. Counter-intuitive, right? Well most knock comes at points farthest from the spark plug, where unburned air/fuel mixture auto-ignites before the flame front reaches that point. The higher flame speed allows the flame front to burn that mixture before it auto ignites, plus with the fuel being more resistant to auto-ignition, it reduces the tendency for an engine to knock.

12/6/2005 7:20:01 AM

^You're right about self-ignition temperature. One thing about Wankels is that they produce a great amount of chamber turbulence, thus homogenizing the air-fuel mixture and eliminating hot spots.

Most spark knock is the result of unburned air-fuel mixture being compressed by the flame front to autoignition temperature and subsequently detonating.

12/6/2005 10:12:17 AM

Quote :

"The jet-ski probably has a compression ratio on the order of 5 or 6:1 if it's a two stroke"

yeah stock is around 6:1 I believe. I remember seeing that number and thinking damn that's low...but I guess it is pretty normal for 2 strokes

12/6/2005 11:47:15 AM

man, i bet that thing sounds like a hopped up weedeater.

12/6/2005 10:47:29 PM

Dont they all, haha. David the frc looks sick now put the TT's on that bitch

12/7/2005 9:28:13 AM

^^ it sounds better since I ditched the N1's, which the previous owner had put in. The chambered-style Racing Beat mufflers make it a bit more throaty, but the headers and straight midpipe make it scream up top.

The deepest it sounded was when I had the resonator and cat on there... it also dynoed 144whp. Fuck that.

12/7/2005 10:39:09 AM

Here's a question. When I replaced my wires, I just used some carquest 7mm replacement shit... would I benefit from like 8.5mm Accel or Magnecore wires? Would that help my breakup? Or is it just the the timing you think? I just think it's weird that I'm getting breakup but when I set my timing at the dyno last year and it had no problem, and that was with the old worn out wires. Of course I was making less power then...

12/7/2005 12:24:55 PM

Im going to say timing still

12/7/2005 1:21:29 PM

dane where is the rpm on that graph???

[Edited on December 7, 2005 at 1:48 PM. Reason : .]

12/7/2005 1:48:03 PM

I didnt scan it in because it showed the afr charts also and I didnt want ppl to knoow how much I had left in the car.

12/7/2005 8:20:10 PM

12/7/2005 8:40:41 PM

Quote :

"3rd gen fuel pump"

used?

12/7/2005 8:53:08 PM