Josh Dashnaw

So my nine year old keeps asking me how much horse power my rx7 has, and I tell him 250 but I have no idea.Can anybody venture an idea, here is waht I have.

1990 jspec turbo II
8.5# fidanza flywheel
FMIC with 3'' piping
2.5in freeflowing exhaust back to 2'' y pipe with dual monza pacesetter exhaust
720cc primary and secondary injectors
rtec 1.8
ported wastegate
I plan on running 10 psi boost
stock turbo and no engine porting
aftermarket intake
Rats nest removed
Air pump and A/C removed
thermowax removed
about the only thing I kept was BAC

Other stuff not related to horepower so much
hallman manual boost controller
knock off brand BOV
koyo aluminum radiator
Thank You for any imput on this.

Furb

iTrader: (2)

250 sounds about right

Your exhaust seems a bit small, and your ic piping seems a bit large

REAmemiya_fan

Tell you what, that small diameter exhaust piping isnt helping your power causes any.

Edit: damn you furb, i post this and you beat me to it by like no time ay all lol

flaco

iTrader: (7)

215 to 245

Josh Dashnaw

yeah I thought it was 3 in for the longest time because that is what I asked the shop to use, and just recently found out it was 2.5
Will 3'' really make that big of a difference with stock turbo.

REAmemiya_fan

It will be easier to build boost and thus increase power. its all weird tricky math (for an NA guy like me) but a more turbo smart person could help out more

Furb

iTrader: (2)

3inch exhaust is pretty much the standard and that fits the stock turbo well.
with your setup (apart from exhaust) and those injectors you could up the boost to 14psi and run close to 280-300hp if you get it tuned properly

Josh Dashnaw

When You say tuning proberly. do you mean with a standalone? All I have right now is the rtec 1.8, and I plan on getting a wideband O2. Does the stock ecm have some tuning capabilities.
Sorry I really don't know much about the vehicles yet, but trying to learn as much as I can.

dwb87

iTrader: (22)

^ Yes. I believe Furb is referring to an aftermarket EMS such as Haltech, A'PEXi Power FC, Megasquirt, Microtech, etc... The Rtek, giant intercooler piping, and small exhaust will hold you back from reaching your desired goal.

Here's a website that may help you a bit when determining a HP level. -> FC3S Pro: From Mild to Wild Power


I originally went with 3" intercooler piping on my last FMIC set-up. Bad idea. The piping was so thick, was way too long, and poorly routed (too many bends). The intercooler probably could have been a bit smaller too. I really lusted over a V-mount set-up, but didn't have the tools to make one at the time. I still made 322 RWHP on 12 PSI, but I could have definitely made more HP with way better response had I truly researched and thought about the whole set-up.

sharingan 19

iTrader: (16)

Pushing that kind of power on a stock turbo (which will eat itself if run at those boost levels consistently) would require more than a 1.8 to be safe. The 2.1 could probably do the job, but I wouldn't run the stock turbo that hard regardless (unless you had water/alcohol injection).

Read the entire archive.

BASTARD

iTrader: (4)

depends on what you mean???... if you're talking a quick 15 second run on a legit dyno, probably 200-225.... that thing will melt if run on the freeway for more than a mile at speed

RXSpeed16

iTrader: (41)

If you haven't upgraded the fuel pump, I'd suggest you take care of that ASAP. An FD or walbro pump would suit you just fine.
I'll go with 234.7 bhp @ 10 psi. But with the flywheel, you should easily be as fast as a 250hp fc.

The stock and rtek ecu's do not learn. They just use the maps programmed into them.
You're running a pretty standard setup, so there really isn't any need for a wideband, yet.
If you change the turbo or get a programmable ecu, then a wideband is pretty much a necessity.

I'd qualify this as a statistical outlier. A stock turbo will not usually pump enough air for ~370 at the flywheel. Even with all the supporting mod's, that's double the stock output in the S4 and well into BNR stage 2~3 hybrid territory.

dwb87

iTrader: (22)

^ I apologize. That was on a BNR stage 4 with other supporting mods. (That definitely should have been included.)

For some reason I didn't even think about the turbo. :-/ I was trying harder to make a point about air flow, from intercooler to exhaust... And the turbo has A LOT to do with that. Yes, the stock turbo will definitely hold you back from achieving our desired HP goal.

Josh Dashnaw

Didn't actually have a HP goal. Everything started when I had the exhaust put on and got fuel cut so I got bigger injectors and new intercooler and computer so it all worked right. Eventually I will have to rebuild my rotary and that is when I plan on getting bigger turbo and standalone. For now I'm fine with my setup whatever the horsepower is, as long as it is running good.
I have been thinking about fuel pump so I'll probably do that and eventually get exhaust redone with 3''. Drives me crazy how that shop did my exhaust and didnt do 3'' like I requested.

dwb87

iTrader: (22)

Look into porting the wastegate passages on your turbo. It's a great preventative modification.

FC3S Pro: S5 Turbo Wastegate Porting

REAmemiya_fan

He said in OP that its ported. Now how large is a good question.

dwb87

iTrader: (22)

^ Man, I feel like I am seeing things that aren't there... And other things I am completely missing. For some reason I could have swore he said he was boost creeping really badly. :-/

I need to stay away from the forum for a bit. I've been way too sick lately.

Josh Dashnaw

Yeah I did say I was getting boost creep. The turbo is currently off and being ported. I'm porting it myself following that same thread you posted.

RXSpeed16

iTrader: (41)

Highly suggest doing a fuel pump ASAP. You are about making out the stock pump. An Fd pump will probably be sufficient until you do major upgrades. Or a walbro if you don't mind running a bit rich.

Furb

iTrader: (2)

I never had troubles with the stock turbo running 14psi.
Ran it for 3 years like that, trackdays and all and the whole unit is in perfect condition.

sharingan 19

iTrader: (16)

Time is irrelevant, its more a matter of miles, your car looks too immaculate to be a daily....
Also, the starting condition of the turbo is important, a low milage or freshly rebuilt unit will fair much better than a tired and abused unit.

Furb

iTrader: (2)

The majority of People who daily drive an FC do not punish it every time it is being used.
i may not do as many miles as them, but my engine gets (ab)used every single time and it is the high boost runs that were supposed to kill the turbo.

A tired and abused turbo will blow up anyways, regardless the boost level.

Rob XX 7

iTrader: (8)

never got the whole daily driver gets more abuse thing?

If anything someone who takes their car out on the weekend will probably subject it to more abuse then someone driving everyday.
I purposely drive my car somewhere I can open it up and enjoy it, I aint driving it to the bank at 30mph.