slammin86

why is it bad to run boost in 5th gear?

CRX T-Si

Because you'll be going too fast and you'll be endangering yourself and others that is on the road.

DENCIO

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX T-Si &raquo;</TD></TR><TR><TD CLASS="quote">Because you'll be going too fast and you'll be endangering yourself and others that is on the road.</TD></TR></TABLE>
yup..like he said

slammin86

does it cause it to overheat?

Joseph Davis

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slammin86 &raquo;</TD></TR><TR><TD CLASS="quote">does it cause it to overheat?</TD></TR></TABLE>

Do you have mechanical problems, or a poor tune?

JDMs1eeper

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX T-Si &raquo;</TD></TR><TR><TD CLASS="quote">Because you'll be going too fast and you'll be endangering yourself and others that is on the road.</TD></TR></TABLE>

I go into 5th gear just after the 1/8 mile. But its all good I'm at the track

(gotta love GSR gearing on a low revving B20 turbo )

TurboLSVtecTeg

Now depending on where this is being done at i.e track,street.

On the street it isnt really a good thing and can cause overheating in certain cases. What happens is that 4th and 5th put more load on the engine and therefore create more heat. This raises your EGT's and can(not always) cause blown headgaskets, melted pistons. Now this isnt going to happen on everycar. Depending on the tune.

Now if your looking at it from a racing standpoint. In most factory 5-speed manual transmissions. The gearing in 5th is lower then a 1:1 ratio(basically overdrive). What happens is that you cant get the maximum acceleration out of the car because the gearing is meant for cruising and not accelerating. Unless your going for a top speed run. This is why depending on gearing, tire size, redline etc. . You factor all these in so that at the end of the quarter you are around your peak power in 4th gear. Because usually this is the closes to a 1:1 ratio without going under and therefore causing slower acceleration that you would have in 5th gear. I could get more technical about this subject, but ill leave it at that.

Sal

ek9vboi2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM S1eeper &raquo;</TD></TR><TR><TD CLASS="quote">

I go into 5th gear just after the 1/8 mile. But its all good I'm at the track

(gotta love GSR gearing on a low revving B20 turbo )</TD></TR></TABLE>

i hear yah! boost lag? lol....

JDMs1eeper

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ek9vboi2 &raquo;</TD></TR><TR><TD CLASS="quote">

i hear yah! boost lag? lol.... </TD></TR></TABLE>

lol not really...

2.8 60 ft time (bogging out badly from runing too rich down low )
13.90 @ 105 on 5psi

when i get teh fuel to act right it sees full boost at 4k, gotta love ballbearin turbos.
(70 a/r 64.5 trim)

ek9vboi2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM S1eeper &raquo;</TD></TR><TR><TD CLASS="quote">

lol not really...

2.8 60 ft time (bogging out badly from runing too rich down low )
13.90 @ 105 on 5psi

when i get teh fuel to act right it sees full boost at 4k, gotta love ballbearin turbos.
(70 a/r 64.5 trim)</TD></TR></TABLE>

i was just joking about the turbo lag. i have a t3/t04b and its great. 4k full boost, wish i had a ball bearing turbo.

best i ever ran in my car was a 13.9 @103 on 10psi. bad launching...friend keep telling me the car dips back down in the front a lot when going into 2nd. plus i was on 17s...o well. need more practice

JDMs1eeper

Nice

Sprockets

iTrader: (6)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX T-Si &raquo;</TD></TR><TR><TD CLASS="quote">Because you'll be going too fast and you'll be endangering yourself and others that is on the road.</TD></TR></TABLE>

I hope this was a joke. If not, give me a break. I hate it when people act like they never speed on public roads. If you're on a smooth highway with no traffic, it's fun and relaxing to open it up.

Until I get my EGT gauge installed, I've avoided boosting in 5th for too long.

CRX T-Si

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B16A Grenade &raquo;</TD></TR><TR><TD CLASS="quote">

I hope this was a joke. If not, give me a break. I hate it when people act like they never speed on public roads. If you're on a smooth highway with no traffic, it's fun and relaxing to open it up.

Until I get my EGT gauge installed, I've avoided boosting in 5th for too long. </TD></TR></TABLE>

This is not a joke but you have to understand one thing sir. You don't wanna encourage such driving habits to people you don't know. I never said I don't have fun, I mean that would be illegal(IMO).

Not everyone is a good driver and when you tell the wrong person you will only make it worse so I rather discourage such action(s).

Sprockets

iTrader: (6)

I see your point, but he wasn't asking for someone to preach the dangers of speeding in 5th. His question was obviously related to what damage can be done to the engine by doing this. Everyone knows that if you drive like a maniac, you risk death. This is a forced induction tech forum. A better response would be to first answer his question, then ask him to do make sure this is done on a stretch of road that he knows well, and not to weave in and out of traffic. By answering his question, you're by no means encouraging irresponsible driving.

MidShipCivic

I speed through school zones @ dismissal in 5th gear

WrongWD

iTrader: (1)

@400 rpm, right

jdmsiR20

hey flame me or whatever.. i dont care..

so what do folks do on long drives? i cant imagine driving to and from work (30mins - 1hr?) in fourth gear.... i'm not stupid or anything, dont need to speed and ****. but from the sounds of people's respones, i should avoid 5th completely... which is completely insane...

so i can drive in 5th, just dont boost it in that gear for too long, right?

racinskittle

You can boost in 5th gear, but yeah like they said before, it can build up heat so dont do it if you dont have to. If you're cruising you're in vacuum so you're fine. Even if you have to speed up to pass a car its not a problem.

It's a very simple concept.

Tuning like always is key though.

Joseph Davis

I've always boosted in 5th gear, with impunity. You have to make sure that you are running a nice rich mixture to prevent the combustion chamber from getting overhot.

It's not rocket science, it's redneck common sense.

jdmsiR20

thanks folks


what, however.... do people do on long drives? i cruise at around 75-80mph if i'm going to be on the freeway for a while... (60+ mile trip).... making my rpm on the stock d.series tranny at around 3-3.5k.

what if i'm getting into or already am in boost at 3k? am i forced to drive at 60mph the entire way?

SiRkid

no one is encouraging anything from what I can see and really dude will speed on public roads if he wants to or not regardless of what people say here.

usually people dont boost in 5th cause it is the most load on the motor and in the past most cars werent tuned so hawt especially in the fmu days and th emotors are more prone to breaking doing that.

cruise in 5th all day ..... thats NO WORRY at all.
if your just cruising you dotn ahve enough load on the motor to be in boost..youll be in vaccuum.

when people are talking about being careful is when you are boosting(ie hammering it) ..cruising= no boost.

Nick7

Hmm... this thread has gone way out of control.
On open roads I usually 'cruise' at 110-115mph... on my D14 engine I'm usually at boost lik 2psi at that point. Sometimes I need to slow down due to traffic, and then again accelerate, all in 5th gear, and while accelerating 'slamming' it to 8psi, and later keep at ~2psi. The part of road I usually drive like this takes almost half hour. So far I didn't have *any* problems due to this, even running with FMU.

What I want to say:
If you have good AFR's, if you have good EGTs, if yr timing is correct (no detonations, etc), if you can cool yr engine enough and yr oil temp doesnt skyrocket -&gt; you should be fine boosting in 5th gear for prolonged periods of time.
At that point it's same as driving stock turbo car at faster speeds.

donkiman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nick7 &raquo;</TD></TR><TR><TD CLASS="quote">Hmm... this thread has gone way out of control.
On open roads I usually 'cruise' at 110-115mph... on my D14 engine I'm usually at boost lik 2psi at that point. Sometimes I need to slow down due to traffic, and then again accelerate, all in 5th gear, and while accelerating 'slamming' it to 8psi, and later keep at ~2psi. The part of road I usually drive like this takes almost half hour. So far I didn't have *any* problems due to this, even running with FMU.

What I want to say:
If you have good AFR's, if you have good EGTs, if yr timing is correct (no detonations, etc), if you can cool yr engine enough and yr oil temp doesnt skyrocket -&gt; you should be fine boosting in 5th gear for prolonged periods of time.
At that point it's same as driving stock turbo car at faster speeds.
</TD></TR></TABLE>

eh u cruise at 115 mph?

Nick7

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by donkiman &raquo;</TD></TR><TR><TD CLASS="quote">

eh u cruise at 115 mph? </TD></TR></TABLE>

Errr.. yea

No offense, it's not like bragging or whatever, but I do drive at that constant speed (175-180km/h) - it is on a.. what in Germany they call Autobahn ... so it's not a 2-way traffic. On 2-way traffic if road is straight is more like 100mph