Just wondering who is running a MP on their stock motor and if you are, how many miles on the motor and what mods do you have...

I have 84k and motor has mid 8s across the compression board and pulls a 17 in vacuum. Has a solid 10.5 to 11 psi of boost...I am just aching to try the midpipe but most everyone says "Ohhhh, Dude, you gonna blow your motor!"

Anyway, would like to see your stock motor setup..

Peace out!

 

I have a midpipe on my stock motor as well. 51k miles on it and get about 16 vacuum with solid 12psi boost. Mods are in sig.

 

I drove with a midpipe on a stock motor for 35k before coolant seals went. I don't seea problem as long as you have some kind of ecu and control spikes.

 

Apnea,

I see that you have a PowerFC which is good. __IF__ you tune the powerfc properly, you can probably use a midpipe.

You will need to keep a close eye on your air/fuel ratios and raise your boost slowly until you get it in the "sweet spot". By this, I mean that with every pound of boost, you make more power and more heat. When you find the point where more boost is mostly just going to more heat and not any real power to the wheels, dial it back a pound or two to be safe.

IMO, you need to do this on a dyno so you can see your AFRs and your power to the wheels.

Brian

 

I had my PFC tuned on a dyno a couple of weeks ago but the MP wasn't on there yet. It was done by Chris at RP...he told me he richened it up a bit when it's at high RPM to be on the safe side...I also have the DEFI EGT Gauge..do you think this is sufficient to watch the ET?

Here's my dyno sheet from that tuning session RP Dyno Sheet

I think I may just try it for ***** and grinns...gonna need a rebuild anyway

 

I have my cat removed and my car came this way - so I'm basically running a midpipe. No other mods, yet.
85k miles on engine.

ProfecB, Efini Y-pipe, boost + a/f gauge, DP coming soon. Then some ECU (will limit the boost with ProfecB until I get the ECU). As there isn't anywhere near any rotary tuner (or at least tuner with WB 02) I'm leaning towards reprogrammed ECU or maybe pre-preogrammed PMC PFS.

 

Apnea, I remember you posting that you were goin down there... I think I even passed you coming back from Dallas that weekend. Anyways.. your A/F on your dyno plot still looks a bit lean huh? Atleast you have a PFC to play with for when you throw on the MP.
Ive had a DP sitting in my closet waiting to get some Fuel Management before I throw it on. Im getting anxious and decided to throw it on during a nice weekend and keep the silencer on the exhaust to prevent boosting over 11psi.

 

Hey Heatreated, Yeah I passed through OKC around 9:30 - 10:00pm on the 31st on my way to T-town. Car is kicking some serious ***....nice not to have any coolant or oil spots on the ground and solid reliable boost...I think I am going to put the MP on in a few weeks and play with the PFC and richen it up a bit to be safe.

 

Thanks for the dyno sheet...

Now I am not any sort of expert on tuning. But I would say that if you're at mid 11s to 12.0 with no midpipe and you add the midpipe without testing again, you might be in for a rebuild in short order. Especially in the summer when your intake temps jump up 50-60 degrees. (dunno where you live, but I'll assume it's cold there now!)

On my car, the midpipe made a HUGE difference in top end power. It felt faster at 10 psi with a midpipe than it did at 12+ psi with the cat. So please be careful.

You don't have to go to a "rotary shop" if you just want to do a pull and check your AFRs... just take it to the nearest dynojet and do a run on there with a wideband monitoring and see how it does. Make sure to give very clear instructions to whoever is operating the car if it's not you stating under what conditions you want them to lift off the gas.

 

What conditions would I want them to let off the gas?

 

Well I have a gutted cat which is just like a midpipe except the stock piping is 2.5" I believe. I was thinking of putting in a restrictor plate in if I went full 3" SS midpipe. I have a K&N filter, SS DP, Greddy SP cat back. boost controller, for my performance mods. With this on a cold cold night I'am hitting 11 psi spike to about 12 psi max. I do have a M2 ECU stage 3 but I thought with the gutted midpipe that the boost would hit a little higher than that but it never did, so I never used it. I'am going to be putting it on real soon just to see how it works. I've heard and believe that as long as you stay near stock psi (12 max) you will be fine with as many bolt ons as possible(with stock TT of course). I havent had a problem with it. I'am afraid if I put an intake on is when it will shoot my boost up. I wil lbe getting a PFC and intake together and take it to get dyno tuned right away. So basiclly if the intake is a little restricted it should be alright.

Also(don't know for sure) but I heard that the 93's seem to have a problem of boost creep and spiking really bad where as the 94's+ have minor problems compared wiht the same amount of mods on all years. If you do get ready for some awesome power and stinky air!

 

If you want solid, reliable boost, then the midpipe is prolly not the way to go. I saw some serious creep (to 13-15 psi), and that's *with* a ported wastegate. Be careful.....

 

Probably the best thing to do is put it on when I have money for the rebuild

 

Na don't do that, just gut the main cat or get a mid pipe, get a SS stencil and have a 2 1/2" cut out and slap it on in the middle of the flange meets. Worked before, then when you are ready to remove it, remove it.

 

QUOTE]Also(don't know for sure) but I heard that the 93's seem to have a problem of boost creep and spiking really bad [/QUOTE]


I agree with that Street King. I have a '93 Touring and my only mods are a DP and airbox mod with stock airfilter (k&N comes in this week) and I'm hitting a solid 11-12 with an occasional spike to almost 13! Not good at all, especially witthout even having a cat-back on yet. Any good ideas on a way to control this? Would the Home Depot boost controller help on boost spikes?[

 

I don't understand the point of putting in a MP and then adding in a restrictor because the MP is too unrestricted. Why not just keep the cat? Your exhaust won't sound like ****, you won't have to deal with the toxic fumes, and you don't have to worry about boost creep and a blown engine.

 

I've had a MP on my stock engine FD for a long time, no real problems. I ran it before on an M2 Stage 3 ECU and now on the PFC, I had some creep issues, but was able to tune them out on the dyno.
I don't know why RP was so worried about blowing your motor, why would it be any different on a new motor?
Just as long as you don't have creep issues, and have it tuned, I don't see any reason not to do it.

 

I'm running a midpipe with a 2" restrictor plate. I STILL overboost when it is around or below freezing. it is very controllable (atleast in the lower from 40-70 degrees. Very much above that and I have trouble making 12lbs in the upper end of the rev range. Just a little FYI and perspective on how much temperature affects boost with a open exhaust

 

With my mods is it possible to use the EGT to monitor when you should actually let off the throttle? (providing there are no spikes or creep) What I am thinking is that since I have the defi with the flashing warning light, is there a high reading on the EGT that I should look for when running the MP that indicates it's running too lean...If I am correct the hotter the EGT is the leaner you are running, right? so what would be the temp that I don't want to go above?

 

Ok, so I think I may go with the MP and try it first without the restrictors and then see what it does...if it starts to spike or creep then I will add a restrictor plate.

I did some searching on restrictor plates and it doesn't seem that anyone sells them...or do they? if they don't do you think it would be worth making up several sets (of what sizes?) if more people need them? I am asking because my company works with this huge metal shop and I could look into the cost of making a few or several sets of different sizes...maybe make a set of 2 or three restrictor plates...2", 2.25", & 2.5" something like that.

Let me know what you think