IMRC

98SNAKE · 04-10-2001, 10:40 PM

Whats up all my mod motor friends? I just wired open the butterflys on my IMRC's to my 98 Cobra. I was wondering if this was a smart move or not. Any comments would help. I also just purchased pulleys and the wms velocity tube with out the meter.Thanks for thoughts on my recent buys would be great.

97snakedriver · 04-11-2001, 12:29 AM

Well about the IMRCs. You'll lose low end torque and make no more high end hp then you were before, so I'd say: Bad idea.

What kind of pulleys did you get?

The velocity tube seems to be good for a few ponies at the very top end.

98SNAKE · 04-11-2001, 06:44 AM

I ordered the MAC pulleys. Would you think that with other mods I can get that torque back? Say like the DIS-4, wires, MAF, and a chip burned.Or do I have to put on new IMRC's? I already have an X-pipe w/o cats flows, and a 3:73 rear end, which I want to change to 4:10. Any other tips would be great.

King Snake · 04-11-2001, 08:59 AM

I agree w/97snakedriver about the IMRCs. These engines need all the torque they can get. I also have a cold air kit, mine is MAC. It made a noticable difference in acceleration, but it also made the idle a little rough. As far as the plug wires go, they will not increase power.

------------------
'97 Cobra, Rio Red, MAC Cold Air Kit, 3.73s, NGK V-Power
BBK H-pipe w/cats (Coming Soon!!)

97snakedriver · 04-11-2001, 12:44 PM

The only modification I've found that has noticably increased low end torque is the Steeda timing adjuster. Gears help by letting you get into the power band quicker, but if you pulling them out anyway, why not step up to a 4.30?

Other then it has a "soft" rev limiter the MSD wouldn't do much for you right now either. The stock ignition is actually pretty good. There is no reason to replace it unless you're supercharged, turbo'd, NOS'd, or revving the motor well past the stock redline.

Do the MAC pulleys have a harmonic damper on the crank? If not, I would reconsider.

As far as the IMRCs, did yours break? Why did you wire them open? You CAN pull the throttles and shafts out, then plug the holes. That would give you a bit more high end power at the cost of low end though.

98SNAKE · 04-11-2001, 06:45 PM

Well I just got home from work were I unwired the IMRC's and hooked every thing back up. Mine were'nt broke I just figured if there are runner controls in the aftermarket that are free flowing why not wire the stock ones open. I'm not sure on the pulleys. What's going to happen if they don't have a dampner? I do know that the crank pulley is aluminum. What pulleys would you use. The 4.30 isn't to much for an every day driver? With the 3.73,xpipe-cats, and flows I spin like crazy at the track to a 13.74@107mph.

97snakedriver · 04-11-2001, 08:59 PM

Wow. You need some drag radials or other traction device! 107 trap is good for a potential high 12 ET. What are your 60' times looking like? The advantage is more pronounced on DRs, but a steaper gear and practice on it, will probably net you a mph or 2 and a tenth or two in the 1/4. Either way I think a set of slicks or high sidewall DRs (275s on a 15 inch wheel) and a ballsy launch could net you over half a second on the strip.

Personally I have 4.10s for two reasons. 1. When I got them 2 years ago people told me I was crazy for going that high and at the time I don't think there were the speedo correction devices other then the gears. 2. I'm going to supercharge, and even on beefy street tires 400+ rwhp is a lot to control. If you are planning on supercharging then 3.73s may well be enough. If you are staying NA then the nature of the engine is to make power high in the RPM, especially after the typically breathing and exhaulst modifications. All the fast NA guys (low 12s) are running atleast 4.30s and usually higher.

The only after market IMRC product I know of is the FRPP delete kit, which is they remove the throttles and shafts, apoxy the holes and charge you something crazy for your trouble. Anyway for just random knowledge the 98s have a bit better IMRCs then the 96-97s. They're a tiny bit bigger and the throttles are made of a plastic as aposed to aluminum for a bit better heat insulation.

If the Mac pullies don't have a damper then its not the end of the world, but it would make me sleep better if they do. I haven't heard of anyone in a Mustang EVER doing it, but I have seen a few Hondas spin bearings (ouch! and ouch$) because of non-damped pulleys.

I'm using Steeda pulleys which are either relabeled ASP pulleys or the other way round, or they both just look and weigh exactly the same.

Either way, they're bullit steel and have a nice damper.

98SNAKE · 04-11-2001, 09:43 PM

Thanks for all the tips. I'am getting a set of 275/40/17 nitto drags in a couple of weeks so I think those will help with the traction problem.

King Snake · 04-12-2001, 11:45 AM

Will those fit on your factory wheels?

97snakedriver · 04-12-2001, 12:38 PM

Oh yeah, the other bad thing about the MAC is I don't think you can use the Steeda timing adjuster with them.

AutoX281 · 04-12-2001, 03:06 PM

I think that the largest "recommended" tire size for factory 17x8s is 255/40/17. 275s usually require a 17x9, though you might be able to squeeze them onto the stock rims...depends on how well that bead wants to stock.

------------------
98 GT Conv: K&N, Pro-5.0, MSD wires

98SNAKE · 04-12-2001, 05:24 PM

I guess I will just have to send the pulleys back. Because my next mod will be the steeda timing adjuster. Will the tires hurt me if they are to big? Our should I just put on the 255's. And how much more would the 275's help.

04-13-2001, 01:58 AM

You have lot to learn grasshopper.

If you want to learn more about getting into the low 12's with a stock-motor N/A Cobra, just ask.

Later, Jason

------------------
N/A 1997 Cobra

1/8 mile - 7.83 @ 90.08 MPH
1/4 mile - 12.26 @ 114.02 MPH
1.64 60 ft.

04-10-2001, 10:40 PM	#1
98SNAKE Registered Member Join Date: Apr 2001 Location: Sterling Heights,Michigan Posts: 129	IMRC Whats up all my mod motor friends? I just wired open the butterflys on my IMRC's to my 98 Cobra. I was wondering if this was a smart move or not. Any comments would help. I also just purchased pulleys and the wms velocity tube with out the meter.Thanks for thoughts on my recent buys would be great.

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04-11-2001, 12:29 AM	#2
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	Well about the IMRCs. You'll lose low end torque and make no more high end hp then you were before, so I'd say: Bad idea. What kind of pulleys did you get? The velocity tube seems to be good for a few ponies at the very top end.

04-11-2001, 06:44 AM	#3
98SNAKE Registered Member Join Date: Apr 2001 Location: Sterling Heights,Michigan Posts: 129	I ordered the MAC pulleys. Would you think that with other mods I can get that torque back? Say like the DIS-4, wires, MAF, and a chip burned.Or do I have to put on new IMRC's? I already have an X-pipe w/o cats flows, and a 3:73 rear end, which I want to change to 4:10. Any other tips would be great.

04-11-2001, 08:59 AM	#4
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	I agree w/97snakedriver about the IMRCs. These engines need all the torque they can get. I also have a cold air kit, mine is MAC. It made a noticable difference in acceleration, but it also made the idle a little rough. As far as the plug wires go, they will not increase power. ------------------ '97 Cobra, Rio Red, MAC Cold Air Kit, 3.73s, NGK V-Power BBK H-pipe w/cats (Coming Soon!!)

04-11-2001, 12:44 PM	#5
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	The only modification I've found that has noticably increased low end torque is the Steeda timing adjuster. Gears help by letting you get into the power band quicker, but if you pulling them out anyway, why not step up to a 4.30? Other then it has a "soft" rev limiter the MSD wouldn't do much for you right now either. The stock ignition is actually pretty good. There is no reason to replace it unless you're supercharged, turbo'd, NOS'd, or revving the motor well past the stock redline. Do the MAC pulleys have a harmonic damper on the crank? If not, I would reconsider. As far as the IMRCs, did yours break? Why did you wire them open? You CAN pull the throttles and shafts out, then plug the holes. That would give you a bit more high end power at the cost of low end though.

04-11-2001, 06:45 PM	#6
98SNAKE Registered Member Join Date: Apr 2001 Location: Sterling Heights,Michigan Posts: 129	Well I just got home from work were I unwired the IMRC's and hooked every thing back up. Mine were'nt broke I just figured if there are runner controls in the aftermarket that are free flowing why not wire the stock ones open. I'm not sure on the pulleys. What's going to happen if they don't have a dampner? I do know that the crank pulley is aluminum. What pulleys would you use. The 4.30 isn't to much for an every day driver? With the 3.73,xpipe-cats, and flows I spin like crazy at the track to a 13.74@107mph.

04-11-2001, 08:59 PM	#7
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	Wow. You need some drag radials or other traction device! 107 trap is good for a potential high 12 ET. What are your 60' times looking like? The advantage is more pronounced on DRs, but a steaper gear and practice on it, will probably net you a mph or 2 and a tenth or two in the 1/4. Either way I think a set of slicks or high sidewall DRs (275s on a 15 inch wheel) and a ballsy launch could net you over half a second on the strip. Personally I have 4.10s for two reasons. 1. When I got them 2 years ago people told me I was crazy for going that high and at the time I don't think there were the speedo correction devices other then the gears. 2. I'm going to supercharge, and even on beefy street tires 400+ rwhp is a lot to control. If you are planning on supercharging then 3.73s may well be enough. If you are staying NA then the nature of the engine is to make power high in the RPM, especially after the typically breathing and exhaulst modifications. All the fast NA guys (low 12s) are running atleast 4.30s and usually higher. The only after market IMRC product I know of is the FRPP delete kit, which is they remove the throttles and shafts, apoxy the holes and charge you something crazy for your trouble. Anyway for just random knowledge the 98s have a bit better IMRCs then the 96-97s. They're a tiny bit bigger and the throttles are made of a plastic as aposed to aluminum for a bit better heat insulation. If the Mac pullies don't have a damper then its not the end of the world, but it would make me sleep better if they do. I haven't heard of anyone in a Mustang EVER doing it, but I have seen a few Hondas spin bearings (ouch! and ouch$) because of non-damped pulleys. I'm using Steeda pulleys which are either relabeled ASP pulleys or the other way round, or they both just look and weigh exactly the same. Either way, they're bullit steel and have a nice damper.

04-11-2001, 09:43 PM	#8
98SNAKE Registered Member Join Date: Apr 2001 Location: Sterling Heights,Michigan Posts: 129	Thanks for all the tips. I'am getting a set of 275/40/17 nitto drags in a couple of weeks so I think those will help with the traction problem.

04-12-2001, 11:45 AM	#9
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	Will those fit on your factory wheels?

04-12-2001, 12:38 PM	#10
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	Oh yeah, the other bad thing about the MAC is I don't think you can use the Steeda timing adjuster with them.

04-12-2001, 03:06 PM	#11
AutoX281 Registered Member Join Date: Mar 2001 Location: San Jose, CA Posts: 27	I think that the largest "recommended" tire size for factory 17x8s is 255/40/17. 275s usually require a 17x9, though you might be able to squeeze them onto the stock rims...depends on how well that bead wants to stock. ------------------ 98 GT Conv: K&N, Pro-5.0, MSD wires

04-12-2001, 05:24 PM	#12
98SNAKE Registered Member Join Date: Apr 2001 Location: Sterling Heights,Michigan Posts: 129	I guess I will just have to send the pulleys back. Because my next mod will be the steeda timing adjuster. Will the tires hurt me if they are to big? Our should I just put on the 255's. And how much more would the 275's help.

04-13-2001, 01:58 AM	#13
jmeiers Guest Posts: n/a	You have lot to learn grasshopper. If you want to learn more about getting into the low 12's with a stock-motor N/A Cobra, just ask. Later, Jason ------------------ N/A 1997 Cobra 1/8 mile - 7.83 @ 90.08 MPH 1/4 mile - 12.26 @ 114.02 MPH 1.64 60 ft.