t_g_farrell

iTrader: (1)

Unless you balance the mixture entering the cats, they will just burn up. Plus you lose the flow the system is
designed to deliver. Why?

racerx01

Everyone I have every talked with about Racing Beat systems has said the same thing. Expensive, extremely well made, extremely durable, and worth the money in the long run. I even talked to a premier exhaust fab shop near me, guy had been in business for over 15 years. He builds with only stainless and has proper bending equipment. He has vast experience with FC, and FD... making both exhaust and intercoolers. He said that for a production performance exhaust system that there is nothing that comes close to RB.

He also mirrored the comments made by others on site that the street port system would be his choice in case in the future you add more porting or carb size; you would not have to worry about needing to upgrade exhaust again.

I was impressed with the thickness of the flanges and quality of the welds. Can't to get them on the 7.

chuyler1

iTrader: (1)

T_g, honestly, just to keep the smell down lol. My REPU has a 2.5" short primary system made up of RB components. It smells pretty bad, so for my FB, I want power, but not really smell. Don't have to worry about emissions in NH.

t_g_farrell

iTrader: (1)

If the smell is a concern, check the mixture, a leaner mixture will smell less. Also don't over do it
on premix (if you do) as that can make it smelly as well.

You could go with the RB single pipe and keep the cats I think, maybe. Not up on the FB exhaust
setup.

racerx01

Well I have the system in. Man what a difference; I now believe the hipe... significant increase in mid and high range power. Now just chasing what I believe is small vacuum leak; the idle is very weak and low.

I do not think I need to bump idle up, do I?

GSLSEforme

SE or non SE? Should run same as before exhaust R&R. No reason for vacuum leak,straightforward swap... what is idle rpm currently?

t_g_farrell

iTrader: (1)

You may want to adjust the idle mixture to be a bit richer, the RB exhaust setup
will lean it out a bit as it breathes a lot better than stock. Also may want to bump
up the timing as well. I think RB makes some recommendations for that as well.

racerx01

GSLSE - its a stock 12A with little over 35K on it. Going to double check for vacuum leaks and see where that leads me. Ordered replaced air check gasket from Atkins if I need it in the future.

Forum - Thanks for all the help.

Maybe I will post video of it running.

chuyler1

iTrader: (1)

Sorry, misread, disregard.

GSLSEforme

How was it idling/idle speed previous to exhaust removal? Really shouldn't have changed that much with RB system install. When you say weak,how so, is idle speed hunting around,does it sound rough,how low is it idling? Perhaps a slight mixture adjustment/idle speed increase will resolve your problem. Before you do that,do a visual inspection. Don't see anything causing the issue, with engine idling ,lightly spray carb cleaner around carb base & rats nest area and listen for a change up or down in idle speed. You can then zero in on the actual cause. Another option i prefer is to use an unlit propane torch with propane turned on slightly and wave it around the same areas with engine idling, a vacuum leak will pull in propane and make idle speed change like carb cleaner,just less messy. Happy hunting,post back with what you find.

racerx01

Well spent about 30 minutes hunting for vacuum leak, spraying carb cleaner. No luck. Before install it had low idle probably around 500/600 rpm but did not hunting and had real smooth idle.

After install idle has dropped 100/200 rpm and bogs when leaving from a stop. Idle is weak and stumbles; if idle was stronger it would sound a little like a mild street ported motor. Have to feather clutch a little to prevent stalling when leaving from standstill.

From 2000 to 7000 it rips, no hesitation or flat spots. The car really has woken up; it leaps forward between gear and revs very strong. While driven in neighborhood at say 20 mph at 2-2.5K it seem lumpy.

All gauges oil temp, oil pressure, water temp, etc... no change. Changed plugs, wires, and fuel filter the month before.

Starting to think maybe carb might just be gummed up. Might try some Lucas fuel/carb cleaner in next tank of gas. Maybe I am being too picky? I have a "fat nikki" heading my way soon anyway so if the carb is worn/gummed, its gonna get changed out in the near future anyway.

Glad I went with this RB exhaust system, been very very pleased so far.

GSLSEforme

There's always at least a slight change in driveability when a free flowing exhaust system replaces the oe-on any car. Sounds like your car wasn't idling perfectly beforehand. Would be worth the effort to adjust mixture & bring idle speed to about 800 rpm. Certainly would improve driveability. 35k on 30+yr old car surely will have some dirt in carb which may or may not affect way it runs. Lucas/Seafoam in tank can't hurt,maybe take peek at fuel filter and see if any junk has accumulated in there. If so you'll want to address that before plunking a fresh carb on there. Also check your centrifugal & vacuum advance on distributor to make sure they work properly. Over the years have seen a couple cars where grease that lubes advance mechanism had dried up and gotten "tacky" somewhat preventing smooth advance of ignition timing. Make sure both leading/trailing vacuum advance canisters hold vacuum and vacuum is present at hoses connecting to canister nipples. These two systems are responsible for smooth driveability/power/fuel economy. Finally check and set initial timing,if you're going to do this, set timing first as it will affect idle speed . Then make your carb adjustments. Little time spent investigating,making adjustments here can make a big difference in how car starts and runs.

rwatson5651

iTrader: (5)

^^^
Perfect advice

Toruki

Great suggestion. I checked my vacuum advance for leading and trailing, matches specs, seems to move smoothly.

Any quick clue on how to check the centrifugal? Simple as timing light and reving it?

In case folks are curious, vac specs are:

Leading vac advance 0° at -100mm Hg to 4.5° at -190mm Hg
Trailing vac advance 0° at -100mm Hg to 15° at -400mm Hg

GSLSEforme

Don't have fsm at hand for ca specs. Was trying to give racerx01 some info on how to work his way thru his driveability problems and eliminate each subsystem as a cause. In his original post he stated he was a mechanical novice. To check ca timing, warm engine,disconnect both vacuum advance canisters & plug hoses. Hook up timing light to L1 plug wire and check for mark at idle,slowly raise engine speed,watching timing mark advance,til it advances no more. Have someone note what tach reading is at this point for reference. At this point #s aren't important it's a quick & dirty check to make sure it's working like it should. Timing should advance in a linear fashion steadily with no jumping around. It should return to base timing at idle. If ca does not do this consistently,it needs some attention. His comment it runs great between 2-7k rpm is why i suggested looking into the basics. Could be carb related,this is how you systematically diagnose what it isn't

Toruki

Thanks GSLSE! I sort of realized after I posted that I had hijacked an RB exhaust thread for this CA question. I suppose the topic "evolved". Anyway you post great, practical information and I appreciate your answer.

For the curious, here are the CA specs:

Leading is 0° at 500 RPM, 10° at 1750 RPM

Trailing is 0° at 500 RPM, 15° at 1750 RPM

GSLSEforme

No worries,Toruki. Yes,thread has evolved. You can always start a new thread for questions. Just trying to help out my fellow rotorheads,my rotary Karma,lol. Its paid off, couple members here have helped me out in a few instances. Wondering if racerx01 will update where he is with his driveability problems.

chuyler1

iTrader: (1)

I got my street port long primary system installed today. Took me 6 hours total working solo with just jack stands and hand tools. Below is the nitty gritty details...

Air pump came out first, two 12mm bolts and two hoses to pop off.

Next I removed the header heat shields. 6 10mm bolts, one snapped off, two are accessible from under the car.

Next was the air control valve, 3 12mm bolts and a hose going to the cat.

Then the 4 14mm bolts for the header. I left the header attached to the cat.

Then I snagged the two 12mm bolts that attached the other cat hose to the intake manifold.

Under the car, I removed the lower heat shield for the mid pipe to gain better access to the bolts attaching the silencer to the midpipe.

I had to grind off the bolts for the midpipe. They wouldn't budge even with PB Blaster and an impact wrench.

The bolts for the mid pipe to the cat came right off.

Next I started removing hangers and pulled everything out.

Installing the new exhaust was covered by others but I basically dropped the header in, hand tightened the bolts. I put the silencer in, hand tightened the hangers. Then lifted the mid section using a jack and slid in bolts. I attached all the hangers and tightened everything front to back.

racerx01

Well have not had time to go hunt for problem again thanks summer time flu. Gonna to check it out maybe next weekend, currently getting ready to go a vacation. If its a carb issue, I got my "fat Nikki" carb this weekend so I got that covered if its carb related. But want to make sure its not a vacuum issue.

Also the 12A is pretty fresh 35K on it, PO had it replaced after she overheated and blew it up. And she had carb float replaced a few years after that (about 8 years ago).

The gas treatment made no difference in idle issue.

chuyler1

iTrader: (1)

Mine actually idles around 800-900 now instead of 750 (just eyeballing the gauge) for what it's worth.

7aull

iTrader: (2)

chuyler - Note no heat protection btw intake and header. Any running issues?

Stu Aull
80GS
Alaska

chuyler1

iTrader: (1)

Not yet, and I wouldn't expect to with an otherwise stock setup. The factory heat shields aren't for heat protection so much as heat gathering. They don't allow for any airflow except to suck warm air off the manifold to aid emissions on cold starts. Furthermore, the stock intake has coolant passing through it.

I have run a similar setup (RB header, stock intake, no heat shield) on my REPU. No issues when towing a camper on 90 degree days.

If you aggressively port your motor, block off the coolant outlets and use an aftermarket intake, and ditch the snorkel air filter assembly for a carb topper like Racing Beat filter, then it's a whole different story and you'll probably benefit from a shield that directs air passing over the header straight back instead of allowing it to swirl around the engine bay.

Jeff20B

iTrader: (13)

The stock intake has ACV which carries some exhaust through it, which carries some heat with it. Too many noobs block off their coolant ports, then wonder why their intake manifold feels hotter. You gotta block off the ACV port in the intermediate plate too. I clean the iron really well and use quicksteel.

wankel=awesome

Why hasn't this guy tried adjusting his idle speed/mixture screws on the carb?

I'm not sure if I missed it, but I can't believe that it hasnt been mentioned lol

GSLSEforme

In his first post he stated he was a mechanical novice,i know at least t g farrel and myself suggested it. He may not know how...my thinking would be good idea to learn how to adjust this one. New carb he mentions will likely need some adjusting also,not likely a bolt on and go. It's probably very close but will need minor adjusting.