EviLPeNeviL

iTrader: (2)

So I have only cb as performance mod. That was all I really wanted for now because I don't want to take the chance of blowing my motor.

My best was: 212.9rwhp and 206.1rwtq. I do get the perfect boost pattern of 10-8-10 but near the top of 4th gear my 10lbs drops slowly and stays at 8lbs for like the last 1krpms or so before redlining at 4th gear.

Another thing is that my A/F ratio was off the chart. After 4.2k rpms my air would drop down and disappear off the graph (lowest point point on graph was 10) and I would assume that it's just 100% fuel after that? If so I should be shooting flames like mad? But I'm pretty sure I'm not SHOOTING flames because I've had at different times had my friends drive behind me while I try to shoot them, but there aren't any, closest was when they saw a blueish flame at the tip of the exhaust and that was it. So if I'm running rich and I'm not shooting flames, then my igition is on right?


Here is one solution that I can think of, it's my spark wire installation that I did several weeks ago, I think I may have plugged in one of the wrong wires which would cause really advance ignition.

Another possibility is that I am waiting to get my dp installed and stock air box modded, that should lean it out some more, but if I'm getting 100% fuel, then the car won't run either because there's no airflow right?

What do you guys think?

-Dan

cavellm

212 isn't bad for just a cat back. Before I bought mine, it had an efini y pipe and a high flow cat. It dyno'd at 216. Your biggest gain will be getting a downpipe, since that's the biggest restriction.

EviLPeNeviL

iTrader: (2)

Yeah but shouldn't a healthy stock 7 dyno at around 225hp to the wheels?

I will get the dp on and then do the air box mod then I will go back and see what I get, if I spike or creep Im gonna change that air box back to stock until I get an ECU.

-Dan

Bucrx7

First, Nice dyno numbers with just a catback. Second if you plugged the wires the wrong way you wouldn't be making that much power. Third you won't be spitting any flames because you still have your main cat installed. Once you install your downpipe you may experiencing a little of boost spike, the dp will make a BIG difference.

Mr rx-7 tt

iTrader: (5)

Those arn't horrible numbers. You should purchase a dp, big difference.

BoostedRex

I should have a nice DP with only 6k miles on it for sale in the next week or so. If you are interested let me know and we'll work something out. Good dyno numbers bro. Laterz.

Zach

EviLPeNeviL

iTrader: (2)

Thanks for the offer for the dp guys, but I bought one the day before the dyno day, I didn't wanna screw anything up like breaking the studs and not be able to drive my car at all for a while, and plus I also wanted to really compare for myself what the dp will do once I get it installed and re-dynoed.


Anymore ideas to my weird A/F problem?

Thanks for the replies.

-Dan

BATMAN

Like Chris said, a down pipe will help alot........... Also a simple K&N replacement filter might help, especially if u have a dirty stock filter..........

Bucrx7

It doesn't seem like you have a A/F problem at all. The stock ECU was programmed to run rich. You can have an intake, dp, catback and the stock ecu will run it fine only if you keep the boost at 10 psi. I believe the stock can run a full exhaust if you keep the boost at 10 psi. Every car is different and is in different conditions, the only way to see if your car is rich enough is to hit the dyno again with your mods.

Tad

I think a healthy stock 7 will dyno at more like 205-210rwhp

Rated R1

Those #'s don't sound too bad. Check out my results from last week.

https://www.rx7club.com/forum/showth...highlight=dyno

rx7machine

Nice numbers man.

EviLPeNeviL

iTrader: (2)

Thanks for the assurance on the dyno # guys, I guess I was just expecting a bit more.

RatedR1, your A/F graph looks KINDA like mine execpt that after 4.2k rpms the line disappears down the graph so we have no idea of how it curves after that.



Oh one more thing, did anyone find it strange that my boost dropped down 2lbs near the top of 4th gear from 10lbs to 8lbs? Minor boost/exhaust leak somewhere?

Thanks again.

-Dan

Mahjik

iTrader: (1)

A stock FD should be close to this:

At WOT, 3d gear, everything stock, boost cycle is (rpm's approximate):

rpm psi
3,000 10
4,500 8 (as 2d turbo comes on)
4,500+ 10 (recovers almost immediately)
6,000+ 8 (and holds to redline)

http://www.scuderiaciriani.com/rx7/boost_test.html

JspecFD

iTrader: (2)

Thats expected/stock behavior.

Qball

as everyone says.. its all NORMAL.

here's my dyno run

https://www.rx7club.com/forum/showth...ighlight=qball

the A/F is so rich after the spike it drops off the chart and never gets to 11.

you can safely add intake, downpipe, and exhaust. that's what i had on this run.. and yep.. 8psi.

at least slap on the downpipe for reduced engine bay heat and more power.

rynberg

EvilPenevil:

The last time I dynoed at ATP, I hit 240 rwhp with a downpipe and cat-back. My boost pattern was also 10-8-10 then falling to 7 at 6k and holding to redline. It's normal. Your numbers may be a bit low due to your pre-cat. Once you get a downpipe, I'm willing to bet your numbers will be close to 240.

Your A/F ratios are spot on. Mine dipped to below 10:1 at the transition and stayed there until 7500 rpm (where it rose all the way to 10.2:1!).

I think it is difficult to hold 10 psi until redline with the stock airbox and filter. I'm pretty damn close with using a Greddy ProfecB boost controller (9.5 psi or so).

EviLPeNeviL

iTrader: (2)

Hey I remember Zerobanger was talking to me about you about your dyno numbers, sounds pretty good to me man. How far are you from ATP?

And thanks for all the replies guys. Will be installing my HKS dp coming Friday and possibly a K&N filter.

-Dan

greg schroeder

I have a gtech pro meter which I use to test modification gains. I set the weight within the little computer to 3040lbs and use second gear pulls for the HP reading.

gtech meter

I just thought I'd add to this thread by sharing the HP I gained by replacing the front cat with a down pipe. It seemed it was a good idea to fix the down pipe I purchased as that the font flange which mates to the engine exhaust wasn't even close to being a match. I ground the metal away which obstructed flow. I also polished the inside of the new down pipe about eight inches down. In addition to the down pipe I also ground the welds inside the stock exhaust to near flush, leaving a bit so the weld could still do its job. Depending on temperature outside, RWHP now reads about 230 on the gtech meter. Before the down pipe and weld grinds the reading was right about 200 RWHP.

Here's a picture link of the clunky weld which still exists in my front cat which is no longer on the car. This type of weld was removed from the front side of the main cat, back side of the main cat and the stock cat back.

clunky weld inside stock exhaust

I should also add the back flange of the down pipe which bolts to the main cat was welded on by the manufacturer cocked and resulted in an exhaust leak once bolted up to 70 ft lbs on lubricated threads. I used two new gaskets to allow for a bit of squish to remedy the situation. I also added a bracket to bolt the down pipe to the transmission as that the original front cat had one and the new down pipe didn't. Without a bracket I just can't see the advantage in having the entire exhaust system rocking on my turbos each time I launched and stopped.

EviLPeNeviL

iTrader: (2)

I was told that I will not pass smog like this........ Because I'm running too too rich? Don't they smog it at like 3k rpms or something?

-Dan