Sounds like you didn't have ARP headstuds to begin with. Half *** build will result in problems down the road. Lesson learned.

 

No it didn't have studs to begin with. It was a stock ls motor and still is minus the studs. That doesn't mean it's a 1/2 *** build at all.

 

Unless you got something to prove, boosting and engine that wasn't designed for boost without proper measures is a half *** build. You can't tell me your surprised that the stock components couldn't take the stress when you significantly increased the output of the engine. It was not engineered to withstand the abuse that comes from forced induction. Can they do it? Sure, they are built well. Many people have proved this... In my opnion if you didn't take safety measures or do anything to strengthen your stock engine you were:

a). looking to make power on a stock engine just to prove a point
b). too cheap to pay the money to do the work

Do you think an EVO or a WRX has a warning in the owners manual about not boosting in 5th gear? People must never do it because they don't seem to be blowing up left and right.

 

Pardon me, but when at track. I boost 4th gear for several second. So you're saying, you can go all out on 1st,2nd and 3rd as long as you can but not on 4th or 5th due to high load?

 

I'm not even responding to you anymore after this b/c your just an idiot. It's blatantly obvious by the past 2 posts.
People boost stock motors all the time without adding head studs and this by no means would make it a 1/2 *** build. Your A scenario makes no sense to me at all. Who am I proving a point to? Scenario B is just nonsense. Boosting a honda motor is not cheap at all. Even if you didn't buy name brand or new parts. Secondly I don't have to worry about paying a shop for anything cause I can fix my own car. I was just simply giving my experience with 5th gear boosting to the Op but as usual some "donut puncher' with a opinion has to chime like always on H-T. Have a nice night D bag!

 

When your car is tuned on the dyno the pulls are done in 4th gear typically. 5th is just bad business all together. Can melt pistons,head lift,put a rod through the block and so on and so forth.

 

Can't accept constructive criticism then don't post in a public forum.

How much boost were you running on your 5th gear pull when you lifted the head? Lemme guess, 10 or more?

 

Since I obviously don't know what I am talking about, perhaps you can continue to educate us some more...

Why are dyno pulls typically done in 4th gear?

Why would I "melt" as piston if my car is TUNED correctly?

Why would my head lift if my car was TUNED correctly?

Why did the rod break? It only breaks in 5th gear?

 

Being "tuned" correctly doesn't mean that the engine would not be prone to damage from high load conditions. the tuner calibrates load, fuel, and timing in an optimal condition for the best/most gears used possible. This calibration can't always predict the higher stress levels of heat, because in the "tune", unless you're doing a full test in ALL gears, there's no way to calibrate for the heat that was never experienced on the dyno. A "tune" can help the driver keep the car in working condition, but it DOESN'T prevent any driver stupidity. This exigent heat from being in 5th gear too long could result in anything from lack of oil in the bearings creating rod knock, to a melted piston, to a lifted headgasket or some other fatique. There's no guide for which will happen when.

4th gear is used mainly because most dynos need a 1:1 engine/load ratio. For hondas, 4th gear which means that the power path goes directly through the mainshaft of the transmission and is most accurate in determining driveline loss, which is why it is used most.

 

While many transmissions link the mainshaft to the output shaft for 4th gear giving a 1:1 ratio, Honda's are not that way.

4th gear is very near to 1:1 on most of the Honda transmissions but there is no way to directly link the mainshaft to the differential in this application.

 

We never had a problem with 5th gear pulls. But to be true we do not feel very well with it. There is always a crazy feeling in the stomack.

On german road conditions it is easy to do 5 gear pulls and it is not illegal to drive as fast as you can. Some other shops have problems with 5 gear pull on hot weather conditions but they usually go with half size radiators and just build "big turbo setups"

We believe and found out that if you design a setup very well (real big full size radiators, oil coolers, good fans, good venting and ducting, good manifold design, intelligent heat shilding and a good tune) there is no problem with that.
But to be true all these things cost money, time for R&D and most people do not want to spend it because they do not understand that it needs more than just an big turbo to build a very cood/fast/reliable car.

Lot of people spend a lot of money for things they do not need but do not spend a dime for things that make cars reliable...

 

4th gear is used mainly because most dynos need a 1:1 engine/load ratio. .[/QUOTE]


thank you, you beat me to saying it. 5th gear really loads the motor being less than a 1:1 ratio.

and to the post earlier where that guy was after the 'busa and hit 950celcius, thats why you have to have a gauge to watch it creeping up and let out of it.

i know on my car currently (15-16psi or 400whp pump gas) i can do a 3rd gear roll on, hold through 4th and boost in 5th enough to pin the speedo and not see temps over 800. with my gsr trans this whole process takes around 10-12 seconds. all that makes me think how rash it is to be boosting for 30 seconds straight. if (not recommended) you are doing highway pulls with bikes, take advantage of opportunities to engine brake/decel and bring the cyl temps back down

again, get the gauge, put it in and watch it. you will learn a lot about how the motor heats up and cools down with different loads and driving conditions

 

I completely agree that a tuned engine is not immune from stupidity or other damage... but my point still being that if its tuned WELL its going to be pretty damn reliable and should be "good to go" in just about any condition. no? If its 150 outside in the desert, I don't think I would go to the racetrack and put my car to the test, but I feel I could drive with a fair amount of confidence none-the-less. Melted pistons comes from some SERIOUS heat build up. Lean conditions, too much timing, insufficient cooling system ability to remove heat, hot intake charges, etc. These are all things that one SHOULD have under control before you go making some 5th gear or even 4th gear pulls. Spun bearings again come from not only lack of lubrication and heat build up but also from hammering down on the piston/rods. Usually from detonation or incorrect timing. Again, something that should be under control. As for the lifted heads, I have only HEARD (never seen) this happening with stock head bolts which are known to stretch. It goes back to what I was saying earlier about a half *** build.

You can slap a turbo on anything, sure. If you don't take precautions to build things to withstand the increase in stress the engine will see and also to tune the engine well enough, its going to lead to failure. I bet anything that the gentleman who lifted his head on his 5th gear top speed run would have lifted that head down the road eventually under "normal" boosting.

Again, do Subaru and Mitsubishi tell people not to run WRX's and EVO's in 5th for extended periods? I really would like to know.

 

True. I was looking at this from a GENERAL perspective. Until one changes the final drive significantly, 4th gear is the best 1:1 ratio to use. But one should never assume anything.

 

Yes. this is common advice from service departments even on those applications that are factory turbocharged, though because of the relative size of the units, the likelyhood of damage from it is slightly less than in the situation where a much larger, higher CFM - producing turbocharger is used. They don't always expressly state it because they understand that ECU will try to protect the car outside of the wishes of the driver. See, the OEM for these higher performance factory engines expects that someone would be running 5th gear or 6th gear for at least a little longer than what a "reasonable" person would drive in the higher range. So in order to protect their engine from damage they program the stock ecu from the factory (which controls the solenoid to the actuator) to NOT be at full boost at those higher rpm and throttle ranges. That solenoid automatically controls the actuator so that the amount of boost will taper off to a safer level when it sees that the driver is driving in a "spirited" manner.

Example in an STI (at WOT); 1st-3rd, 18psi..... 4th, 16psi, 5th, 14-15psi. This is so that detonation and knock will not occur. The OEM tries as much as possible to protect the owner from himself by having the ECU do all the work. Now, if you use an aftermarket boost controller to basically bypass the stock solenoid and allow a specific level of boost REGARDLESS of gearing or what the computer wants to do, that person will put themselves at higher risk for detonation and damage while STANDING in 5th gear for an extended period of time.

Remember, Turbocharged hondas don't have these safety measures, because they were never from the factory turbocharged (excl. RDX) in the first place. If you look at code from an RDX ECU, the result would be the same as with other OEM equipped turbocharged applications.

 

What it all boils down to is when boosting in 5th gear for an extended period of time, the load on the engine increases further stressing it and creating heat. Good cooling system or not, the more load on an engine, the more prone to knock it will be. Head lift can be prevented by using aftermarket head studs and really should not be the result of detonation. If the setup is properly executed, then the only problem that should occur when boosting in 5th gear is detonation. This in turn will cause pistons to melt and ringlands to crack and other problems associated with detonation. Will it happen everytime you slam your foot through 5th? No but is it something to be worried about? Yes. Just like saying you should never boost an engine without headstuds. Will you encounter head lift the very first time? No but it is very well possible. We are just throwing out possible problems that you may encounter if you boost in 5th gear. You can take this knowledge and do whatever you like.