B heads rev limiter?

Boostang · September 28th, 2009, 10:04 PM

where do the B heads stop making power if anyone knows.. thanks

SWEET2KSTANG · September 29th, 2009, 03:32 AM

the b-heads will make power all over the top end, its the cams and little things like that; that will decide what the motor will do.

Boostang · September 29th, 2009, 02:17 PM

ok.. im doing the 4v swap for the more flow/more rev.. i just dont wanna still be shifting at 6k!

98Cobra_sleeper · September 29th, 2009, 02:19 PM

eh, maybe you should just get a set of c heads. they are torquier and u probably could shift lower

Boostang · September 29th, 2009, 03:45 PM

well the thing is i found a mark vii motor for 350... for everything.. i just cant pass it up.. im looking for some c heads... anyone know somebody?

98Cobra_sleeper · September 29th, 2009, 05:01 PM

ive seen some on ebay. brothers performance actually was selling a new intake manifold thats made for someone who swapped C-heads onto a teksid block that has an actuater that keeps things closed for torque then opens up at high rpm for more power. i think it was a ford racing piece.

Doc8224 · September 29th, 2009, 05:14 PM

Are you asking if you can rev past 6k? or do you wanna know if they make power under 6?

red96stang · September 29th, 2009, 06:37 PM

they stop around 6500-6800

Boostang · September 29th, 2009, 07:26 PM

i was asking where they stop making power??
i just know with these 2v's they cant make power above 6k without the proper head work/cam/intake combo

Doc8224 · September 29th, 2009, 09:35 PM

They will make power to the upper 6k range. The heads aren't the issue at that rpm it starts to be the cams and intake.

bitemark46 · September 29th, 2009, 11:54 PM

cam profile and runner length determine where peak power is. Don't worry if you want to spin to the moon to make power B's are where its at. Be prepared to pay $$$ for a solid 8,500+ rpm valvetrain.

-Mark

Boostang · September 30th, 2009, 12:11 AM

its just a basic 2v to 4v swap.. just trying too see where i need to set my rev limiter for and where these heads will make power.. until i get out of college then these heads will see the 8500 range

ReverendDexter · September 30th, 2009, 12:13 AM

If it helps, the stock rev limiter in my Cobra is at 7k.

acidtonic · September 30th, 2009, 12:27 AM

Just to inform you the B heads in the Cobra and Mark are slightly different actually.

Probably not enough for 90% to care but there is a slight raise in the middle of the two valves which shrouds them that is missing on the Cobra castings. I doubt its of much importance if you go FI but NA every little bit helps.

Are you aware of what else is different from Mark to Cobra? Intake, Cams, Ignition(Cops vs coilpacks), crank, and IMRC actuator.

right off the top of my head I'm going to say ditch the mark intake and cams. Get yourself a nice high rpm capable valvetrain like Mark mentioned. Get a well ported intake... very important as this and the cam are your two biggest sources of power NA. Convert to Coil on Plug ignition, ditch the IMRCs or figure out how to get them working with your computer. Ditch knock sensors since you arent boosting and your valvetrain will be too noisy above 7000 rpm for them to work well anyway... I dont think your computer can handle them anyway. Upgrade your fuel system and injectors. I personally would also go with very light weight rotating assembly and get it balanced well. You are going to be dealing with high rpm or you're wasting your time with these heads NA. They do however have 50cc+ larger ports than any other 4 valve head made and flow like gutter pipes once you get some RPM behind them. Especially with a .20 or more overbore. I've heard that really wakes up the B's.

I'm not an expert so dont rely 100% on what I've said but this should be a rough guide on what you need to do for a good NA B head build.

Boostang · September 30th, 2009, 01:30 AM

i have a light weight/balanced rotating assembly.. i am getting a 97 cobra intake. my motor is bored .020 over. do i just take the imrc plates off or do i replace them with something else?
what are knock sensors?
will 32 pound injectors and 255lph fuel pump be enough?

right when i looked at the mark intake i said and i quote "hell no!!!"

98Cobra_sleeper · September 30th, 2009, 05:11 PM

well the imrc's in the 98 cobra's were plastic. i deleted my imrc's by getting a set of 97 cobra imrc's which were aluminum, and i removed the rods and flaps, then had the holes that the rods went through welded shut. knock sensors retard timing (i think) when the motor detects knocking and pinging?? someone correct me if im wrong. 32lb injectors and a 255 would be enough for maybe 400hp ish, i believe

Boostang · September 30th, 2009, 05:23 PM

so i have to have the imrc plates but i should go to aluminum ones?

ReverendDexter · September 30th, 2009, 05:58 PM

Originally Posted by Boostang

so i have to have the imrc plates but i should go to aluminum ones?

No, he's saying he made IMRC-delete plates from a a set of the older aluminum units.

Boostang · September 30th, 2009, 09:05 PM

oooh i see.. how much will the imrc delete kit run me roughly

98Cobra_sleeper · October 1st, 2009, 07:03 AM

well, you mite not have to. it depends on if your car has aluminum ones or plastic ones. im not sure on the mark8's. if you have aluminum ones, just do what i did. if you have the plastic ones, just do what i did lol! well, MMR makes delete kits, for like 250 bucks! so i did it for roughly 30 by selling my plastic ones, buyin aliminum ones, and then havin em welded up.

September 28th, 2009, 10:04 PM	#1
Boostang Hardcore Enthusiast 1997 Mustang GT 11.01@128.32 Join Date: Jan 2009 Location: Seale, Alabama Posts: 1,747 iTrader: 0 reviews	B heads rev limiter? where do the B heads stop making power if anyone knows.. thanks

September 29th, 2009, 03:32 AM	#2
SWEET2KSTANG mm's nitrous mod 2000 mustang gt 11.79@115.83 (old set up) Join Date: Oct 2006 Location: N.W. AR Posts: 12,540 iTrader: 8 reviews	the b-heads will make power all over the top end, its the cams and little things like that; that will decide what the motor will do. __________________ project warhorse under construction wagon burner under construction as well (04 lightning) being built by MP2 Performance

September 29th, 2009, 02:19 PM	#4
98Cobra_sleeper Enthusiast 1998 mustang cobra Join Date: Jul 2009 Location: pa Posts: 617 iTrader: 0 reviews	eh, maybe you should just get a set of c heads. they are torquier and u probably could shift lower __________________ HP twin turbo - 691hp/608tq with 15lbs huffed in (old setup) comin soon...ON3 turbo kit, PTE7175

September 29th, 2009, 05:01 PM	#6
98Cobra_sleeper Enthusiast 1998 mustang cobra Join Date: Jul 2009 Location: pa Posts: 617 iTrader: 0 reviews	ive seen some on ebay. brothers performance actually was selling a new intake manifold thats made for someone who swapped C-heads onto a teksid block that has an actuater that keeps things closed for torque then opens up at high rpm for more power. i think it was a ford racing piece. __________________ HP twin turbo - 691hp/608tq with 15lbs huffed in (old setup) comin soon...ON3 turbo kit, PTE7175

September 29th, 2009, 05:14 PM	#7
Doc8224 N/A 4v Guru 2003 Mach 1 Join Date: Oct 2007 Location: Afghanistan Posts: 3,463 Blog Entries: 2 iTrader: 1 reviews	Are you asking if you can rev past 6k? or do you wanna know if they make power under 6? __________________ Military Crew U.S. Army Aviation Apache's Lead The Way

September 29th, 2009, 02:17 PM	#3
Boostang Hardcore Enthusiast 1997 Mustang GT 11.01@128.32 Join Date: Jan 2009 Location: Seale, Alabama Posts: 1,747 iTrader: 0 reviews	ok.. im doing the 4v swap for the more flow/more rev.. i just dont wanna still be shifting at 6k!

September 29th, 2009, 03:45 PM	#5
Boostang Hardcore Enthusiast 1997 Mustang GT 11.01@128.32 Join Date: Jan 2009 Location: Seale, Alabama Posts: 1,747 iTrader: 0 reviews	well the thing is i found a mark vii motor for 350... for everything.. i just cant pass it up.. im looking for some c heads... anyone know somebody?

September 29th, 2009, 06:37 PM	#8
red96stang Regular 1996 gt 97cobra boltons Join Date: Feb 2009 Location: north carolina Posts: 99 iTrader: 0 reviews	they stop around 6500-6800 __________________ MM Cobra Club Member #32

September 29th, 2009, 07:26 PM	#9
Boostang Hardcore Enthusiast 1997 Mustang GT 11.01@128.32 Join Date: Jan 2009 Location: Seale, Alabama Posts: 1,747 iTrader: 0 reviews	i was asking where they stop making power?? i just know with these 2v's they cant make power above 6k without the proper head work/cam/intake combo

September 29th, 2009, 09:35 PM	#10
Doc8224 N/A 4v Guru 2003 Mach 1 Join Date: Oct 2007 Location: Afghanistan Posts: 3,463 Blog Entries: 2 iTrader: 1 reviews	They will make power to the upper 6k range. The heads aren't the issue at that rpm it starts to be the cams and intake. __________________ Military Crew U.S. Army Aviation Apache's Lead The Way

September 29th, 2009, 11:54 PM	#11
bitemark46 Regular Join Date: May 2008 Location: Tampa, Fl Posts: 397 iTrader: 0 reviews	cam profile and runner length determine where peak power is. Don't worry if you want to spin to the moon to make power B's are where its at. Be prepared to pay $$$ for a solid 8,500+ rpm valvetrain. -Mark __________________ -Mark- 98' N/A Cobra (Stock longblock) 11.79 at 114.64 (1.62 60ft)

September 30th, 2009, 12:11 AM	#12
Boostang Hardcore Enthusiast 1997 Mustang GT 11.01@128.32 Join Date: Jan 2009 Location: Seale, Alabama Posts: 1,747 iTrader: 0 reviews	its just a basic 2v to 4v swap.. just trying too see where i need to set my rev limiter for and where these heads will make power.. until i get out of college then these heads will see the 8500 range

September 30th, 2009, 12:13 AM	#13
ReverendDexter Priest of the Car Gods Clapped-out '90 GT 'vert ~5.5 seconds off TTOD :( Join Date: Jan 2007 Location: Rohnert Park, CA Posts: 13,808 iTrader: 0 reviews	If it helps, the stock rev limiter in my Cobra is at 7k. __________________ O o /¯/______________________ \|BLAAAAAAAAAAAAAAAAAAAAAAAAARGH!!! \_\

September 30th, 2009, 12:27 AM	#14
acidtonic Hardcore Enthusiast 97 Cobra Join Date: May 2008 Location: Royal Oak Michigan Posts: 1,056 iTrader: 0 reviews	Just to inform you the B heads in the Cobra and Mark are slightly different actually. Probably not enough for 90% to care but there is a slight raise in the middle of the two valves which shrouds them that is missing on the Cobra castings. I doubt its of much importance if you go FI but NA every little bit helps. Are you aware of what else is different from Mark to Cobra? Intake, Cams, Ignition(Cops vs coilpacks), crank, and IMRC actuator. right off the top of my head I'm going to say ditch the mark intake and cams. Get yourself a nice high rpm capable valvetrain like Mark mentioned. Get a well ported intake... very important as this and the cam are your two biggest sources of power NA. Convert to Coil on Plug ignition, ditch the IMRCs or figure out how to get them working with your computer. Ditch knock sensors since you arent boosting and your valvetrain will be too noisy above 7000 rpm for them to work well anyway... I dont think your computer can handle them anyway. Upgrade your fuel system and injectors. I personally would also go with very light weight rotating assembly and get it balanced well. You are going to be dealing with high rpm or you're wasting your time with these heads NA. They do however have 50cc+ larger ports than any other 4 valve head made and flow like gutter pipes once you get some RPM behind them. Especially with a .20 or more overbore. I've heard that really wakes up the B's. I'm not an expert so dont rely 100% on what I've said but this should be a rough guide on what you need to do for a good NA B head build. __________________ Converted to the Dark Side. 06 Apex Silver Evolution IX GSR - Turboback Exhaust, Tune - Wideband O2, Trustz backlight gauges, Apexi turbo timer - Stock wing, but soon to be wingless. - Guessing 280-310 at the wheels. 02 Red Escape V6 4x4

September 30th, 2009, 01:30 AM	#15
Boostang Hardcore Enthusiast 1997 Mustang GT 11.01@128.32 Join Date: Jan 2009 Location: Seale, Alabama Posts: 1,747 iTrader: 0 reviews	i have a light weight/balanced rotating assembly.. i am getting a 97 cobra intake. my motor is bored .020 over. do i just take the imrc plates off or do i replace them with something else? what are knock sensors? will 32 pound injectors and 255lph fuel pump be enough? right when i looked at the mark intake i said and i quote "hell no!!!"

Remove Advertisements Sponsored Links
Ford Mustang Forum Advertisement

September 30th, 2009, 05:11 PM	#16
98Cobra_sleeper Enthusiast 1998 mustang cobra Join Date: Jul 2009 Location: pa Posts: 617 iTrader: 0 reviews	well the imrc's in the 98 cobra's were plastic. i deleted my imrc's by getting a set of 97 cobra imrc's which were aluminum, and i removed the rods and flaps, then had the holes that the rods went through welded shut. knock sensors retard timing (i think) when the motor detects knocking and pinging?? someone correct me if im wrong. 32lb injectors and a 255 would be enough for maybe 400hp ish, i believe __________________ HP twin turbo - 691hp/608tq with 15lbs huffed in (old setup) comin soon...ON3 turbo kit, PTE7175

September 30th, 2009, 05:23 PM	#17
Boostang Hardcore Enthusiast 1997 Mustang GT 11.01@128.32 Join Date: Jan 2009 Location: Seale, Alabama Posts: 1,747 iTrader: 0 reviews	so i have to have the imrc plates but i should go to aluminum ones?

September 30th, 2009, 09:05 PM	#19
Boostang Hardcore Enthusiast 1997 Mustang GT 11.01@128.32 Join Date: Jan 2009 Location: Seale, Alabama Posts: 1,747 iTrader: 0 reviews	oooh i see.. how much will the imrc delete kit run me roughly

October 1st, 2009, 07:03 AM	#20
98Cobra_sleeper Enthusiast 1998 mustang cobra Join Date: Jul 2009 Location: pa Posts: 617 iTrader: 0 reviews	well, you mite not have to. it depends on if your car has aluminum ones or plastic ones. im not sure on the mark8's. if you have aluminum ones, just do what i did. if you have the plastic ones, just do what i did lol! well, MMR makes delete kits, for like 250 bucks! so i did it for roughly 30 by selling my plastic ones, buyin aliminum ones, and then havin em welded up. __________________ HP twin turbo - 691hp/608tq with 15lbs huffed in (old setup) comin soon...ON3 turbo kit, PTE7175

Threads Similar to: B heads rev limiter?
Thread	Thread Starter	Forum	Replies	Last Post
rev limiter	Bush18	99-04	39	April 21st, 2009 10:00 PM
rev limiter	Iownastang	5.0 Mustangs	24	June 8th, 2008 05:58 PM
Rev Limiter?	MamaStang	2005 - 2010	22	May 28th, 2008 08:53 AM
rev limiter???	FoxHoss	5.0 Mustangs	9	October 28th, 2007 02:04 AM
Rev Limiter	adam0421	General Tech	1	October 21st, 2007 05:24 PM

All times are GMT -4. The time now is 02:09 PM.
Contact Us - Modded Mustangs : Ford Mustang Forums - Privacy Statement - Top
Modded Mustangs is ©2005-2008, All Rights Reserved, And is Not Affiliated with Ford Motor Company. Forum is powered by vBulletin ©2000 - 2012, Jelsoft Ent. Ltd. & SEO by vBSEO 3.3.2 ©2009, Crawlability, Inc.