I want to know what it takes to make it safe(r) to boost in 5th gear. I'm debating between the maxrev(t3/t4 .57trim) and Vortech but I would like to know which be easier on the motor at high speeds. I know the Progress/Hondata whatever civic ran 200+ with a b20 and the Vortech and Peter Cunningham runs one on his NSX so the kit can't be as bad as what everybody here says. Anyways, any opinions welcome and thanks in advance.

 

What's your ultimate goal? To boost in 5th gear, or top speed? Really, the biggest problem in 5th is you can be boosting for a LOOOONG time before you run out of gearing. The problem is the heat buildup. I'd say some extremely hefty pistons and iron sleeves would be a minimum. Some extreme method of keeping the internals from melting down would be required as well (ceramic coatings maybe?) Don't forget the rough rule of thumb of a max of 15-20 seconds of sustained boost to keep your internals safe. This is something I've thought about before, but it really doesn't seem worth the trouble to compensate for unless you're going for some type of landspeed record and the like.

Just a few thoughts I've had,

Ryan P.

 

General Rule of thumb...dont base a decision on what Fully Funded Pro Teams are using, because chances are, their setups arent even close to what you'd be getting.

Suprdave

 

couldnt say it better

 

heat building up?? wtf

what info do you have on this?

do you even have a boosted car?

my shitty sohc has seen 6psi in 5th doing 120 on the interstate right before the fuel cut kicked in. my pos is fully stock minus the turbo and ic and i know i was up there for atleast a minute.

disel trucks boost all the time they never break anything. sure they are built stronger but they dont have any heat problems. you get your a/f correct and timing, you will not have any problems with heat.

please show me you basis for these asumptions!

not positive but please check the info on that sc civic i am pretty sure that was an si with a b16 head and a b18b block, not a b20

 

I boost in 5th gear....nothing seems to happen...YET.

 

I hate to sound like a water injection *****, since I've never even used it before (am I a lyricist?). From what I've read it could help out in situations where heat build up is a problem. If you're serious about safely boosting 5th gear for extended periods of time, it may be worth looking into for ya.

 

I was told not to boost in 5th gear because it was the weakest of the gears. Doesn't really make sense to me. I could see why you wouldn't want to boost for longer than 15-20 seconds, but I think that only applies to 5th gear because 5th is the only gear that you could actually boost for that long in.

 

not the weakest- just higher loads can be put on the engine, for the longest amount of time, higher speeds = more wind resistance, even more load on engine, more heat in engine/exhust/turbo.

 

good advice... lots of funding and free stuff vs. our paychecks

 

Yes, turbodiesels are under lots of boost nearly all the time. From the factory they have forged everything (thick rods, pistons, crank) and a generous iron block. My diesel is under boost even at idle!

But also consider diesels run at a far lower operating temperature than an equivalent gas engine, ~250-300F at idle vs 850-900F at idle for a gas engine. Peak EGT is about the same however... mebbe 100F lower for certain types of diesels...

 

I boost in 5th with my jrsc no problems yet, ofcourse I don't do it for long....

 

You guys are awesome. Thanks a ton for all the help.

So the main thing like always is just to have good components and good tuning, right?

FI forum

 

proper fuel and timing

 

 

 

Well, it's pretty much a general known fact that sustained boost creates more heat much by what falconGSR has mentioned the buildup of the load on the engine by wind resistence, and think about this: the longer you boost, the more you heatsoak your intercooler causing higher intake temps leading eventually to detonation (unless you're running a theoretical permanent 100% efficiency intercooler).

I do indeed, although I don't see how this really relates to the discussion...
Congratulations, you made it. Keep going for top speed while boosting and see what eventually happens would be my suggestion.
A diesel motor is a diesel motor. Different than our motors for many reasons...so direct comparisons can't be made. Although it is correct that the most important factor in both is the tuning of the a/f & timing.

These are all ideas and concepts taken for fact in the forced induction world, discussed and upheld in this discussion forum every day.

Ryan P.

 

If your running a JRSC you dont have much to worry about anyway cause they suck. But if you got turbo eventully you will kill your motor.

 

I learned a very long time ago that most people who give out advise, dont have any real firsthand experiance with it.

There are only two ways to blow your motor up by boosting in 5th gear:
1] preignition
2] detonation
and YES, they are two entirely different things.

And another thing, there is no way in hell you will "melt" a piston due to excessive combustion heat. After a while heat soak may cause your motor to detonate or preignite, which will then destroy things. If your motor is tuned properly, it will not blow. You just need to leave a healthy margin of error due to the extreme load.


[Modified by RioNinja, 7:26 PM 11/8/2002]

 

So what exactly is the difference?

 

Boosting in 5th gear and breaking sounds like a myth to me. Boosting in 5th gear for long periods at 20 psi of boost may be bad for the motor but so is gettiing airborne......think about it which one would happen first???

If your tunning is on you shouldnt have any probs in 5th gear.

 

You should have no problems boosting in 5th gear, granted tuning is correct.
All this top speed talk is killing me....ok, ive gone about 155 (very, very scary) in my car on the highway without blowing the motor. Although last week I blew the **** out of my motor and only going 120mph

 

This is the "exact difference".
https://honda-tech.com/zerothread?id=328862

 

LOL some1 tried to compare with diesel turbo engines .. thats hillarious... for 1 SEMI's engines have fully forged internals.. LOL

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rioninja &raquo;</TD></TR><TR><TD CLASS="quote">&lt;BLOCKQUOTE&gt;quote:&lt;HR&gt;
So what exactly is the difference?&lt;HR&gt;&lt;/BLOCKQUOTE&gt;
This is the "exact difference".
https://honda-tech.com/zerothread?id=328862 </TD></TR></TABLE>



That article written by the GM guy should be required reading for everyone who wants to make more power be it supercharge, turbocharge, N20 or just plain N/A. It applies to everything.