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I am building a 7m and i need to know if there is any prevenative measures i can take to prevent a BHG besides a MHG. Or possibly if there is any upgrading i can do to the cooling system.
 

· 475RWHP 449TQ and climing
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YOU NEED TO MAKE SURE YOU HAVE GOOD TUNING...ie NOT TOO MUCH TIMING NOT OVER 11:1 AFR AT wot TO COMPENSATE FOR ANY MISHAPS UNDER BOOST!

TUNING IS THE KEY. THAT SAID MINIMUM 550CC INJECTORS FOR 450RWHP, AND 720CC FORANYTHING OVER 450RWHP.
 

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720's are not much more expensive so if im making around 300-450 range now and plan on going bigger later could i just get 720's they wouldnt be to much would they itll be tuned off a SAFC.
 

· 475RWHP 449TQ and climing
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I'd go 720cc injectors. Think of this ....Toyota gave you 230hp at the fly wheel, and 440cc injectttors which by the way is calculated at the fly wheel. This gives you a 200 hp head room, where as 550cc injecors to the fly wheel, and 450 rwhp means those 550ccs will be peaking soon, and if a strange anomally happens detonation will occur. Going with 720cc injectors again gives a 450-500rwhp at least 200hp headroom. You must have a balanced approach to make hp, and remember rwhp and fly wheel hp power is different. Fuel injectors are calculated at fly wheel hp power ratings. If you account for drive train power loss then 550cc injecors provide about 475_500rwhp, which is a detonation waiting to give you a rod knock blown HG or cracked pistons!
 

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hes tuning with a safc, bigger is NOT better. Things need to be balanced so fuel isnt added or subtracted excessively when using piggy backs.

If it where a full standalone i would definatly double up on the fuel available vs. needed.
 

· 475RWHP 449TQ and climing
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hes tuning with a safc, bigger is NOT better. Things need to be balanced so fuel isnt added or subtracted excessively when using piggy backs.

If it where a full standalone i would definatly double up on the fuel available vs. needed.
Regardless of bigger is not better you need 720cc injectors and you can run 720ccs with an afc. Some of you guys seem to think you Know all the answers, but fail to realize that you need a combination of everything in synch to be optimum, but running lean on fuel is a certain inevitable death. 550cc injectors are for any one making 350-450 rwhp max, and 450 rwhp on 550ccs is cutting it close. Running anything under 720cc injectors is asking for a one way ticket to the rodknock life. Just make sure AfR's are not over 11.7 WOT if using an afc with not too agressive timing and you will survive. Many have done this and have made 600+ rwhp. Also again anything over 450rwhp really needs to be managed with a standalone. :1poke: :)
 

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Regardless of bigger is not better you need 720cc injectors and you can run 720ccs with an afc. Some of you guys seem to think you Know all the answers, but fail to realize that you need a combination of everything in synch to be optimum, but running lean on fuel is a certain inevitable death. 550cc injectors are for any one making 350-450 rwhp max, and 450 rwhp on 550ccs is cutting it close. Running anything under 720cc injectors is asking for a one way ticket to the rodknock life. Just make sure AfR's are not over 11.7 WOT if using an afc with not too agressive timing and you will survive. Many have done this and have made 600+ rwhp. Also again anything over 450rwhp really needs to be managed with a standalone. :1poke: :)
good advice...tell him to get larger injectors than he needs and than tune with a afc. So now he can pull a TON of fuel and at the same time advance the timing considerably. that's the perfect way to get away from detonation!!!

and detonation does not cause rod knock...poor oiling conditions does



OP, do not run 720's on an AFC. I assume you already know about torquing the head higher than factory spec as well as getting arp head studs (as opposed to oem bolts)
 

· 475RWHP 449TQ and climing
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good advice...tell him to get larger injectors than he needs and than tune with a afc. So now he can pull a TON of fuel and at the same time advance the timing considerably. that's the perfect way to get away from detonation!!!

and detonation does not cause rod knock...poor oiling conditions does



OP, do not run 720's on an AFC. I assume you already know about torquing the head higher than factory spec as well as getting arp head studs (as opposed to oem bolts)
I like smart mouth know it all like you. You don't know shit about Supras and you actually think thaat you can teach me something huh. Well Mr. big mouth an AFC is not the optimum way to tune, BUT you can achieve a goal of 600rwhp to the wheels using it. I believe the famous Will Knealy did this and whupped many a cars like this never blowing anyhing. Pulling fuel, and making sure your timing isn't advanced over10 degrees will definitely achieve this goal.

I'll say it again the best way to tune for any motor wanting to make ove 400rwhp is to get a standalone. Many people will not because of the cost. Add up the cost of rod knock and the many blown motors and many will tell you a properly tuned standalone would have cost less.

Detonation over and over again causes the rods to hammer the crank, and each detonation is like taking a hammer to the berings. Ask a real mechanic about that Mr. know it all. Whats riding between the rod and crank ....a thin layer of oil and your berings, and each time the crank comes into contact with the rod bering it causes damage.:stickpoke

As far as torqueing the head you need to have a metal head gasket if that isnt installed, and if one isn't I'd try 72ftlbs of torque, but I wouldn't recomendt that. Getting a metal head gasket for sure will cause less headaches. Read my thread posted on avoiding rod knock in the FAQ forum. BTW my head is torqued to 110ftlbs of torque.

Let me just say I have had a Supra since 1994. I have learned from personal experience what works and what wont. I build my own motors, and have helped others build motors. Every motor that failed me was due to detonation, so I learned the hard way and bought a standalone.:stickpoke

I take motors apart and put parts into a box and put it back together in my sleep. There isn't anyone here that can teach me how to properly build a motor. After making 475rwhp with 449 ft lbs of torque, my car was breaking up at 5000rpms at 22lbs of boost. I then decided to go standalone to take full controllof everything.:gtfo:
 

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the key is STANDALONE. Its a double sided sword with a piggy back. If you can control timing, pull as much as you want with a piggyback. Other wise balance your setups needs.


I have yet to see a 7m that developed RK from detonation. You should blow the rings to pieces along with the HG and piston long before this..
 

· 475RWHP 449TQ and climing
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the key is STANDALONE. Its a double sided sword with a piggy back. If you can control timing, pull as much as you want with a piggyback. Other wise balance your setups needs.


I have yet to see a 7m that developed RK from detonation. You should blow the rings to pieces along with the HG and piston long before this..

This is true however you can just set hard timing a tad lower, or just leave timing set to 10tdc, and make sure your afr's are no more than 11:1-11:7 WOT!
 
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