Anyone running IMRC deletes?

R

Rich88LSC

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I am probably doing a short runner Cobra intake and the guy will make the deletes for me for $25 more. I have heard good and bad about deleting the IMRCs. Anyone actually running these on a Mark?
 
Haven't done it, but considered it since my IMRCs are leaking some air at the o-rings.

The word is that leaving them open will seriously undermine your low end torque and that it's best to only do this if you have some kind of forced induction.

I'd imagine it'd be a real dog around town since most of the time those IMRCs are closed.
 
I heard that but I have also heard that with a good tune it's not that bad and I have a 3500 stall converter and 4.10s.
 
Rich88LSC said:
I heard that but I have also heard that with a good tune it's not that bad and I have a 3500 stall converter and 4.10s.
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I don't mean to discourage you because I'd love to hear some first hand accounts of what happens. The gearing would help, but I still think it'll be a pig coming out off the line or stop light until it hits about 3500 RPMs.
 
When I had my SHO and I had the IMRCs open all the time it was a dog on the low end. It kills low end torque having them open all the time.
 
wood_e said:
It kills low end torque having them open all the time.
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I agree, but the gears and stall should help in that regard since he'll be spending more time further up in the RPM range. That will all hinge on how good the tuner is - and Rich, I would consult your tuner to get his opinion as well. I'm curious to see what he says.
 
If the engine is being the dogged down your loosing power. Gear and a TC will only help mask it, not compensate. I see no reason to remove the IMRCs on NA.
 
unity said:
If the engine is being the dogged down your loosing power. Gear and a TC will only help mask it, not compensate. I see no reason to remove the IMRCs on NA.
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The Cobra guys seem to have better results but that is a lighter typically manual trans car and many of them have 4.30s or 4.56s and rev the crap out of them.

Your right gear and a TC will not fix it just get it into the powerband quicker. Without a tune deletes are a complete waste and the car will be slower. With a tune I'm trying to get first hand experience whether with a tune the top end gains are worth what is lost at lower rpm.
 
It's not going to be worth it for you.
You'd probably be better just having him polish the intake.
 
I stopped by the tuner's shop after work. His opinion is that since the Cobra intake only has one runner per cylinder (unlike the Gen1 Mark intake) runner velocity will not change much whether the IMRC butterflies are open or closed. Most of gains/losses are in the tune and they are minimal on a properly tuned car. Since I'm pulling the intake already and can have them done cheap he advises I have them done for no other reason then to avoid any future problems with them.

So I think I'm going to go through with it. When it's all said and done I will post dyno numbers. with the new setup.
 
I'm confused you are going to use a short runner cobra intake and your asking about the delete. I thought the cobra intake stock hurts the low end power now that you are shortening the runners that makes the low end even weaker. Why would you be worried about around town driving if you're going the short runner way. To me that clearly is an all out push for the max peak power output not drivability. I run my mark with the valves welded open and the control box unplugged, it may hurt the low end. But I don't care when driving around town because at any time other than pulling out from a stop the trans will kick down and hit a sweet spot above low end RPM's. I also have 3200-3500 stall which helps from a stop. I cann't punch it from a stop anyways or it will just smoke-em on the road so I dont know it the delete hurts. I would like to hear your dyno results. I have thought of this same set up.
 
Rich88LSC said:
I stopped by the tuner's shop after work. His opinion is that since the Cobra intake only has one runner per cylinder (unlike the Gen1 Mark intake) runner velocity will not change much whether the IMRC butterflies are open or closed.
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That makes sence unless the velocity in the smaller dual ports is substantially higher than the larger single port. A smaller port can fill a cylender faster than a large port just by the velocity even with less volume
 
I got a set with mine, if you dont use them, sell them at svtperformance.com and get some $$ for them, if they are nice.

But i opted not to do it, i like driving it normally, if i supercharge it and need a little more power, ill put them in. You could always try it, its not that hard to change them out with the cobra intake on.
 
I got the MMR billet polished IMRC deletes, they are very high quality and the fitment is perfect. I haven't driven the car yet, waiting on my C&L intake tube and IAC tube but I'll keep everyone posted.
 
I haven't got my car done either. Money is tight and I decided to do a few more mods while everything is apart. I will definitely post up when it gets on the dyno and when it gets to the track. However long that takes.
 
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