Alright guys once again need your experience and advice in reference to my 2000 FRC. Here is the list of Mods

70,789mi. currently on stock short Block.

PRC stage 2.5 5.3 heads
TSP 233-239, .595/.604, 112ls
FAST 92mm Intake
92mm Throttle body
VaraRam B2 System
Summit 25% UD pulley
LG Streets 1 3/4 long tubes
3" Off Road X pipe
Corsa Pace car exhaust with tiger shark tips
Centerforce Dual Friction Clutch
RAM billet steel flywheel

I had a highway tune done and was left with idle surge, The exhaust fumes are so strong they make my eyes water and my clothes stink. I plan on getting another tune this spring but I am wondering if....Here is where you guys come in.. Should I spend my money and get the TSP 100mm MAF? Before the tune.

 

I'm not sure whether your car has the 78mm of 85mm MAF of the later models. If you have the 78mm it's probably worth finding an 85mm. You don't need the 100mm. The 85 will flow more than you need.

Are you running cats? If not, your exhaust is going to stink not matter how it's tuned.

 

In short, no. A 100mm MAF isn't going to address the exhaust fumes nor the idle surging.

The fumes are most likely caused by two things. No cats and cam overlap. The more overlap your cam has, the more fumey it is going to smell at idle as raw fuel is sucked out the exhuast.

The only reason, I think, you should upgrade to a 100mm MAF is if you've eliminated all restrictions before the MAF by running a 4" diameter intake tube of some sort. Otherwise, the stock MAF is capable of support 600.

 

I agree with the above. Regarding the tune, one thing I have learned from my own tuning is that idle timing can play a huge difference in idle quality, including fumes. This is just a suggestion and an emirical observation that worked on my car. When you say a 'highway tune' that leaves an awful lot on the table as far as info about what the tune actually is.

You have a pretty aggressive mod combo. I'd save the coin on the MAF and put that into a tune from an experienced tuner. Idle surge is usually caused by improper values in the idle tables including spark. This causes transition problems as the computer seeks to maintain stoich while moving from the running state to idle state. So, I'd suggest getting a good tune from a good tuner.

I also agree with WKMCD that if you have a 75mm MAF you would be better off going with an 85mm MAF (unscreened). You will have to recal the MAF table for it to work well, but that can be done during the tune. I don't think you will see any increase in HP, because even though an MAF is an orifice an MAF is just a meter. An MAF uses a thermal transfer function to measure the mass of air moving through it. So a 75mm MAF will measure, say 150 g/s the same as an 85mm MAF will. The only difference being the velocity of the air will be greater with the 75mm MAF. However, at WOT and high HP levels a smaller MAF can contribute to less than atmospheric pressure due to the amount of air that can fit through the smaller opening. This can cause slight levels of vacuum when monitoring the MAP sensor. This will result in slightly less WOT power. An 85mm MAF will reduce this. I'm not sure how much peak power you'd lose between the 2 but the 85mm MAF will give you slightly better 'throttle response', and that is always a good thing. Also, the 100mm MAF's use a different sensor and that can cause problems in calibration. I'd bet you'd run out of cells at the top of your table with a 100mm MAF. I did. See my sig. Sheesh, what a mouthful, sorry.

 

I concur, you have an issue with the tune. I'm not sure what you mean by "highway tune" but I assume is an open loop (full throttle) tune. You need an honest to goodness dyno or street tune to change your closed loop characteristics.

 

No cats, I keep seeing all over the web that a larger MAF seems to increase HP and TQ down low. So I was curious if this would give me another increase in HP.
I am running the stock MAF behind the VaraRam Maybe just the SLP or even the MTI housing would help.

I know that the exhaust will stink but my car is running so rich that it is turning my tail pipes black. I understand that I will not be able to eliminate the smell alltogether.

The surge is only about 40% of the time when I slow down it will drop as low as 400rpm then jump to 1300 then down to 600 up to 1100 and so on...

This Spring JJFormato is going to be in Gettysburg PA early spring. I hear he is the best and he said he could eliminate all the problems I have. I am just wondering if a larger MAF and a set of 42lb injectors would assist in the tune seeing as though they are about all that is left thats still stock.

 

When I had the H/C/I done I wanted everything tuned, it was 500 bucks for a dyno tune or 250 for a highway tune where they tune it basically by ear and handling issues. Guess I wasted my money huh?

 

I cant believe that a tuner would recommend anything but a dyno tune for a head and cam car. Hopefully one of the better tuners here will chime in but I dont think it was money well spent.

 

I cant resist posting since I have had similar probs. Like the guys have said, with these cars a good tune makes all the difference. I had idle surge and throttle hang issues that got to be irritating even after a local tune, finally got Slowhawk (Don Kinder) to spend a morning tuning the thing and now its like the H/C setup came from the factory - just a joy to drive - spend the money on a good tuner.

On the MAF, depending on how much of the intake you are willing to change, you might want to consider the MTI racing composite 78 mm MAF (not sure its still available) the only internals are the wires so without the airfoil stuff the cross sectional area is about the same as a stock 85 W/O the screen. You will have to have the MAF table adjusted but this allows you to keep your existing intake plumbing.

Just my thoughts - hope this helps a bit - good luck.

 

Oh, on the exhaust smell, even with random tech high flow cats I still get some fuel odor in the exhaust. The 38 lb injectors seem to comtribute to that (actually I like the smell, reminds me of my 66 big block). So if the smell really bugs you you might want to rethink the larger injectors as long as the car runs well with the stockers.

 

FYI: I ran an 85mm MAF on my 403 and made over 510RWHP. A good tuner can tell you if you are dropping Kpa's at RPM which is an indication of a restriction before the TB. I seriously doubt you'll have an issue with an 85mm MAF, There are many good tuners around who can help you with this.

I did add a 100mm PowrMaf but I also did this intake at the same time.

 

Nice engine bay. I like the set up a lot. I read an article about the MTI housing and a calloway Honker TB install that netted some hp and TQ down low in the rpm range. So I was thinking about a MAF upgrade. But I am also keeping in ming when I upgrade to the LS3 Stroker that I want the ability to simply swap 80% of my parts over. -heads and cam. I only see a couple MAF's though in the 100mm range.

 

I read above that you are considering 42lb injectors. I would suggest to stay away from those on a 346. They are too big and you or your tuner will have a very hard time trying to keep a decent afr at idle as they will almost surely run at the small pulse limit at idle. I'm pretty close on a 403 and am still playing with that. Also, they actually may be 'sluggish' compared to a smaller injector. I'd suggest a set of 30lb/hr SVO's.

 

A 85mm MAF would help your car if you have a 78mm on there now. The car needs to be tuned on the dyno and the street unless it is a load dyno. A decently cammed car takes a little extra time to tune to get rid of alot of the surging but is definatly worth it. Unfortunatly a lot of shops just tune wot and consider the surging normal to get the car done quicker.

 

Advice noted and appreciated. 30lb SVO's. What about fuel rails? Should I upgrade them as well. The last tuner stated he was thinking I could possibly be maxing out the injectors. So would a MAF/INJ/Fuel Rail upgrade be the best solution to any possible problems?

 

PM sent.

 

"suggested you could possibly be"
???

either you are or you arent,
it would show in your A/F ratio in teh high RPMs and it would show in your tuners logs of pulsewidth and duty cycle on the injectors.

there is no "maybe" about it,
find a new tuner.

 

Read from the top. It was a highway tune.
There is no read out.
No logs.
I am in search of a new tuner but asking my fellow members if they would suggest I get a larger MAF/Injectors/Rails prior to tuning again. This will rid the tuner of all possible problems as far as maxing the F/A ratio out goes. You following me? He would be able to tune the car to its fullest potential.
I want to avoid going to a tuner and at the end he tells me if such and such were larger he could have run it up to XXX... The last tuner shut me off at 6000 rpm. My car is still blistering the road at this point and I am forced to shift. I agree the more I read the more I get steamed about wasting that 250.00.

 

Save the money on the rails. Not needed, unless you want some 'bling'. I'm at 630hp-flywheel and using 42lb/hr injectors and stock fuel rails. What I am getting close to is my fuel pump's max capacity, but that is stock too right now and still no problems.

What I'd suggest you do for now, based on your questions and where your car is at right now is this:
1) Find a good tuner that will add the below 2 components to your system BEFORE the tune:
2) get a known good working OEM 85mm descreened MAF (Delphi) this would be a 2001+ with screen and pull that out, or a Z06 MAF.
3) get a 3pin to 5pin adapter for the MAF since you have a 2000 with seperate intake temp sensor. (it's integrated into the newer MAF's)
4) Get a set of 30lb SVO or equivalent injectors.
When I say equivalent, I mean pintle-style, not disk-style, and 30lb/hr @43psi, NOT 58psi. Most injectors are rated at the 43psi.
Go here for more info: Injector Info
5) Don't install either until you get to the tuner.
Have them install those pieces before the tune. It should take about 1/2 hr for both.
6) They can then read your PCM and then put default values for the associated tables into your PCM and begin the tune.

If you purchase those components and install them into your car without changing the PCM table values for them the car will be VERY out of tune and you could be running so rich there will be a chance of doing damage, (washout, fouled plugs, etc.)... MAYBE, but why take the chance.

 

Your set-up looks similar to my old one. I had the idle surges also, after a base tune to get my car to the tuner after it was up and running. In the time I drove to and from my 1st tuner, my o2's went bad. Get home and something smells hot. Cats were red-hot. Gutted them and went back for a follow-up tune. Was told the new 85 SLP MAF was just along for the ride since I had a Speed Density tune. Was told my issues were a result of too big a cam for a 346 and it is what it is. Had an aggrevating trip home......

Then I saw one of Jeremy's threads about Gettysburg and the rest is history. Great tuner........He will be working his magic on my new Z this spring.....

When my cats were gutted, I had the smell and the exhaust film covering everything back there....another reason why I couldn't sneak up on anyone.

Get to a reputable tuner and let him log some data while putting your car through the paces and if you're lucky, you'll only shell out the cash just once. I paid 1k total between 2 tuners but my issues were solved Give Jeremy a call and if not, theres alot of fine establishments here in the NY, NJ, PA, MD area that could help you out.
Let me know how you make out.

Good luck.....