turbo details and compression for b18c7 question

[votek]

i have recently bought a 2.6mm headgasket for my b18c7. worked out by a known mechanic, the compression will be 9.3

im running a custom turbo kit with a t28 ball bearing from the jdm s15. what would the max psi / boost i would run on my stock motor?

[Q_ball]

Dude, seriously, there's no definite answer to that...
Ive seen stock motors take 12psi for months on end.

All comes down to who you're tuning it with, and with what etc etc.

[DLO01]

Yeh, too many variables man. Setup, tune, how you drive it.

[fatboyz39]

damn this is a hard one.

[Elwood]

i have recently bought a 2.6mm headgasket for my b18c7. worked out by a known mechanic, the compression will be 9.3

im running a custom turbo kit with a t28 ball bearing from the jdm s15. what would the max psi / boost i would run on my stock motor?


How high does your boost controller/wastegate go?

[votek]

that im not to sure. i have a electronic boost controller. just im asking because sr20's with 8.5 compression run up to 15psi with this turbo.. my motor now a 9.3 compression. will it hand at least 10 to 12 psi daily drive

[Elwood]

that im not to sure. i have a electronic boost controller. just im asking because sr20's with 8.5 compression run up to 15psi with this turbo.. my motor now a 9.3 compression. will it hand at least 10 to 12 psi daily drive

Doesnt work like that..

IT IS ALL ABOUT THE TUNE

Like Q-Beezy said, with stock internals DL001 was running 12psi?

And it could possibly even handle up to 16 depending on how it has been tuned. There was an article about this on honda-tech a while back..

[WTNESS]

ive ran 9 psi with stock internals and stock head gasket,

like they said its all about the tune,

if they get the proper air/fuel ratio in then it should handle 10-12 psi

[DLO01]

Na man. I am about 8.5 psi max.

Like I said there is no exact figure. Depends on setup, tune and how you drive....

[beeza]

Q-Beezy :thumbsup: :D

[Limbo]

i'm running 10PSI on a stock build.
heard with a HKS decompressed head gasket you can run up to 16PSI, there was a car running this tuned by Toda.
Maybe PM him and ask.

But it all depends on how long you want it to last.

[beeza]

It's unreal to think just a head gasket can make such a difference.

[NightKids]

damn this is a hard one.

What he said.

[votek]

yeah.. still looking for a tuner in melb :(

oh something else i needed to ask was is the stock honda map sensor enough or do i need to upgrade to a delco 2bar map sensor

[Limbo]

10PSI stock will be fine, anything more need to move up

[OMG.JAI xD]

10PSI stock will be fine, anything more need to move up

2nd that.

stick to the basic rule of 10psi on stock internals.
thats for a daily. day in day out no problems.

the internals of our hondas arent so great when it comes to handling big boost.
if you take a look of some turbo build threads here, im sure youll come along a comparison picture of the OEM conrod compared to a forged I or H beam conrod.
the width and thickness of it is so great of a difference.

the beaut of our engines.
is our cranks.
D series cranks (yes i said D) can handle 400hp+ with only a balance, and aftermarket big end bearings.

if youre going turbo, even planning to run 10 psi, i reckon change some internals while youre at it. better for the long run.
head gasket is just a gasket after all, generally speaking, and changing a compression ratio only makes your engine more tollerant to knocking or less tollerant to knocking.

[DrTran]

Well just consider how well maintained your motor is and how good the person that tunes your car is. If the person tuning your car is good I've seen a stock b16a take 30psi and lasted probably about 25 passes on the track but safely i'd run about 13-14. if your not running a ems.

[VTi_b0i]

honestly man dont lower ur compression! run lower boost instead! ull thank me for it later i garentee it!
say u werent turboing it, u wouldnt lower it! why? cause by lowering the compression you will lose power! AND it will lag alot more because of this! ur better off keeping the motor as honda intended it, just only running bout 7psi like i am... that way ur only adding more power instead of trying to make up for power uve lost by lowering it... do u get me?
ITR motors can handle 9psi very well so i suggest u do that.
and make sure u get a reputable person to do the tuning

[VTi_b0i]

oh, and nothing is better then an OEM head gasket... if i ever blow my mugen one ill definatly go back to oem. (cause my mugen one is for higher compression) lol

[destrukshn]

run lower compression if your going to run more boost through your motor, such as 12psi +
it's safer.
using a t28bb on a standard motor is fine on 10psi, spooling with be quick and reaching full boost under 3000rpm on 10psi.

[destrukshn]

or even 10psi + you might lower the compression.
on a t28bb, just leave it on 10psi, and you should make approx 160kw atw.
depending on setup of course and tune.

[VTi_b0i]

lol did u read what i wrote johnny?
why run more boost just to make little gains? theres no point lowering compression just through a head gasket JUST so u can tell ur mates ur running 12psi of boost etc.. when u could possibly make the same power, on higher compression on say 7-8psi? if uwant lower compression buy a nissan motor LOL

[destrukshn]

yeah, did you read what i wrote? lol hahaha
what i'm saying in conclusion.
lower compression if your going to run more boost
but on a b18c7 standard compression with a t28bb with 10psi
you should see 160kw atw.
maybe more.

IF you want to run more boost lower the compression ratio.

[VTi_b0i]

lol hairy muff my friend...
im just trying to stress the point that hondas are made for high compression and thats how it should remain :p dont lower compression and try and make up for the power loss, leave the higher compression and run lower boost... it works out the same and will be more fun to drive for sure... if u want a lower compression honda motor, buy a VTi-R motor ot b16a :p im runnin about 11.4CR if i remember correctly

[fatboyz39]

high comp + turbo = winnar

[destrukshn]

yes i do admit high comp + boost for hondas are great.
but it also depends on what turbo you want to use, and what power goals your after.
but in voteks case leave stantdard compression, want more power, use a bigger turbo.
lol.

[VTi_b0i]

thank you :)
id rather make say 200kw atw on a standard ITR motor on 8-9psi then make like say 210 on an ITR motor with like 9.5CR with 12psi or so.... the one with higher compression will be more fun to drive

[destrukshn]

lol, your basing it all on the same turbo though?
what i'm saying is that it depends on the turbo your runnign and the power goals you want to achieve as well.
lol.

[VTi_b0i]

well the bigger the turbo, the more CR ud want :p cause that would create less lag :D

[votek]

well if i lower my compression to 9.3 with the t28bb, how much boost can i run and how much power will i make

quote. standard compression, 10psi will maek 160kkwatw

just want to know how much mroe boost i can run with the head gasket and how much more power i will make.

for example

160kw with 8psi on standard head gasket

180 on 10psi with lower comp

[Q_ball]

YOu're still asking questions similar to this one,

"How long is a piece of string?"

[IEVAQ8]

with stock compression on b18c7 u can run watever boost you want...........however, the higher the boost the less timing and the more fuel u need to run to make it last.....
(this is not the optimum way to tune)

with stock comp and low boost the engine will work as though it is standard andf the boost will help it along.......

when u lower compression and run higher boost, the forced air (boost) will stress and strain the internals alot more as the car wont be at its natural high copmp reving ability, hence run more boost to compensate for the loss of comp.

as VTI_Boi has said plenty of times............with stock compression and lower boost, the car as more friendly and responsive to drive compared to low copm more boost.......

either way it will work, but again VTI_Boi has said, honda built b18c7 perfect for NA circumstances, if u add a little bit of boost, u will make power, if u lower comp, u need to run a lot more boost to make the same power...............

good luck Tony

[delsol9000rpms]

i think that summed it up nicely ^^^^

[IEVAQ8]

guys, seriously get over ur lengths of strings................

[destrukshn]

with stock compression on b18c7 u can run watever boost you want...........however, the higher the boost the less timing and the more fuel u need to run to make it last.....
(this is not the optimum way to tune)

with stock comp and low boost the engine will work as though it is standard andf the boost will help it along.......

when u lower compression and run higher boost, the forced air (boost) will stress and strain the internals alot more as the car wont be at its natural high copmp reving ability, hence run more boost to compensate for the loss of comp.

as VTI_Boi has said plenty of times............with stock compression and lower boost, the car as more friendly and responsive to drive compared to low copm more boost.......

either way it will work, but again VTI_Boi has said, honda built b18c7 perfect for NA circumstances, if u add a little bit of boost, u will make power, if u lower comp, u need to run a lot more boost to make the same power...............

good luck Tony
you do not need to raise the boost that much more to make more power btw.
a couple/few pounds will do it. generally speaking.

[IEVAQ8]

you do not need to raise the boost that much more to make more power btw.
a couple/few pounds will do it. generally speaking.

if u lower the comp, u will need to prob run about 8-10psi to make up for the lost comp and a little more power, and to make the power he is looking for, u will need to run at least 12-15psi............so again, on stock comp and 10psi max, u will make same power and more responsive power compared to lower comp and say 15psi.............

its a proven fact............

[votek]

fair enough. im leaving the stock compression and tuning my car.. well the tune is tomorrow *fingers crossed*

[IEVAQ8]

fair enough. im leaving the stock compression and tuning my car.. well the tune is tomorrow *fingers crossed*

good luck, who is tuning it???????????

did u get and exhaust??????

[votek]

chasers motorworks

standard for now.

oh did u guys need a map sensor?

cos they are teling me to buy a delco 2 bar map sensors. is the factory one fine?

[IEVAQ8]

chasers motorworks

standard for now.

oh did u guys need a map sensor?

cos they are teling me to buy a delco 2 bar map sensors. is the factory one fine?

kool, ur wasting ur money with stock exhaust for a tune, it will detonate for sure........too much back pressure, a turbo engine needs free flowing exhaust........

stock map sensor was fine for me...............2 bar...........??? how much boost u gonna run?????????

[votek]

secret ;)

[spsteven]

how did the tune go? im very interested in the results and what you think of the drivability, looking at doing a similair setup soon with stock compression aswell.

[IEVAQ8]

how did the tune go? im very interested in the results and what you think of the drivability, looking at doing a similair setup soon with stock compression aswell.


i wont spoil the owners news..............but it aint the power output he was expecting thats for sure......and he did actually lower the comp and only run 8psi...............mmmmm..........

tell us the news Tony

[votek]

nah i havent lowered the compression yet..

100kw at 3000 rpm. the turbo application is too small. im looking for a 3037 something similiar to yours tom or deans

manifold is on its way. :D

[IEVAQ8]

nah i havent lowered the compression yet..

100kw at 3000 rpm. the turbo application is too small. im looking for a 3037 something similiar to yours tom or deans

manifold is on its way. :D

sorri man, i thought u already did the head gasket, good move u didnt

im sorri to hear man.....but its so funny how i told u so.......lol

the other thing is for all those guys out there that flamed my tuner with my avo kit and my b18cr........well, this is second proof that avo is no good for b18cr as tony used a different tuner............mmmmm..........

good luck with second time man.

if u need any help let me know

[votek]

im having alot of oil issues at the moment

oil is leaking from my head. the spark plug cover bolt and the one connect to the head are snapped and it is leaking my lovely motul oil :(

im also having coolant from the water feed and return lines from the turbo..
anyone selling braided water feed and return lines?? haha thanks

[destrukshn]

if u lower the comp, u will need to prob run about 8-10psi to make up for the lost comp and a little more power, and to make the power he is looking for, u will need to run at least 12-15psi............so again, on stock comp and 10psi max, u will make same power and more responsive power compared to lower comp and say 15psi.............

its a proven fact............
avo turbo kit.
10psi on stock compresion of 10.0:1 made 155kw atw.
12psi on a 9.0:1 approx compression made 160kw atw.
on my own car.
vtir dc2
t28bb.
there is more response with high comp turbos, i am not doubting that.
i'm just trying to prove a fact that you probably don't have to run THAT much more boost to get it as the same peak power as before.

[IEVAQ8]

avo turbo kit.
10psi on stock compresion of 10.0:1 made 155kw atw.
12psi on a 9.0:1 approx compression made 160kw atw.
on my own car.
vtir dc2
t28bb.
there is more response with high comp turbos, i am not doubting that.
i'm just trying to prove a fact that you probably don't have to run THAT much more boost to get it as the same peak power as before.

thats a good experience quote,

i didint mean to say that u had to run 15psi, it was an example tha u need to run more boost with lowered comp to make same power as stock (high comp) and low boost................

[destrukshn]

yes i understand, i was just trying to state, that you don't have to run THAT much more boost to make the power from the high comp motor.
so saying that, if you raise the boost more, you will make more power.
becuase lowering the comp will obvisously allow you to run more boost.
but if you want to make good power on lower boost levels, get a bigger turbo, eg. gt3037
with a big rear housing.

[votek]

yeah i know. but my compression is 11.1 on the b18c7

i paid 140kw at 7psi

[IEVAQ8]

yes i understand, i was just trying to state, that you don't have to run THAT much more boost to make the power from the high comp motor.
so saying that, if you raise the boost more, you will make more power.
becuase lowering the comp will obvisously allow you to run more boost.
but if you want to make good power on lower boost levels, get a bigger turbo, eg. gt3037
with a big rear housing.

its the same principal..........u lower the comp to run more boost, which makes the car lagy.......u run lower boost with stock (high comp) and make same power but heaps more responsive...................


yeah i know. but my compression is 11.1 on the b18c7

i paid 140kw at 7psi

ur issue is that the rear housing is way too small..............if u wanna do budget build, u can get ur rear housing machined to say a 1.06 rear housing as i had 0.86 and was still 2 small..........or keep what u got and get a gt3037 with at least 0.82 rear housing with internal gate and u save heaps on getting new manifold and the likes..............

[destrukshn]

you made 140kw on 7psi?
on a t28bb with a 0.64 rear housing?

[VTi_b0i]

LOL the mechanic said mr rear housing was too big LOL and mine is an .82

[votek]

yeah .. is there something wrong? or is it just me

[votek]

no way. looking for a .86 or a 1.06

[destrukshn]

yeah .. is there something wrong? or is it just me
sounds about right-ish.
dyno figures aren't always the most accurate.
but sounds about right, you reach full boost around 2500 rpm with that turbo
lol

go for a larger turbo. or at least a rear housing, for your turbo, i believe garret only make a 0.86 rear housing for it.
that should add another 20kws ish.

[votek]

i just thought it was a bit low lol

would it cost alot of moeny to change the rear exhaust housing

or do you think i should upgrade to the disco potato.. aka gt-rs

i was pretty dissappointed

[votek]

wait.. so mine is a .86 housing... hrmmm interesting.. lol

[destrukshn]

your are only running 7psi of boost.
it does seem a tad low, but you have the most ugliest dump pipe in the world. ( i'm also using the same manifold and dump pipe btw hahaha)
rear housing would set you back around 600 brand new from garret, or you can just get a disco potato, a 2871r, or something similar along the lines of so with a 0.86 rear housing or larger.
changing the turbo helps alot, BUT, also getting rid of the manifold and dump pipe also helps make easier power.
atm, i'm pusing 205kw atw with the avo manifold and dump pipe. hahaha, sure it's restrictive, but it's still making power.

btw what exhaust are you running? 2.5inch?

[destrukshn]

wait.. so mine is a .86 housing... hrmmm interesting.. lol
i dobut your one in s 0.86 rear housing?
who said so?
im pretty sure your one would be a 0.64 housing, the most common rear housing on the t28bb

[VTi_b0i]

im using a garret GT28RS (disco potato) and its alot of fun on the street

[IEVAQ8]

tony, ur t28 s15 jdm spec bb turbo is a 0.64 rear housing........

on that t28 i would go for at least a 1.06 rear, even get it custom machined and fitted (bout $700) that inclkude machine work, biger exhaust wheel and balancing...........

i had the 0.86 rear, and i had same issues as u..............

[votek]

what rear exhaust housing have you got now?

[IEVAQ8]

im running a gt3037s with 0.82 rear housing.

and if u see my comparison with avo graph...............same response as a t28bb with 0.86 rear housing......

http://i287.photobucket.com/albums/ll147/ievaq8/avo-vs-full-race-power.jpg

[votek]

whats full boost at for you tom?

[IEVAQ8]

whats full boost at for you tom?

Atm, the way my car is set up…………….coz im not running a boost controller………..

The more I rev the more boost I make………does that make sens…………

It makes 7.5psi, consistently after 7000rpm………

However I am on 5psi at 4500 rpm and its not laggy at all…………….just like my comparison avo setup to fullrace setup graph shows………..

Here is my full race and gt3037s boost graph


http://i287.photobucket.com/albums/ll147/ievaq8/boost-level.jpg

[votek]

yeah what you said was right. my limited was down to 7000 and when they revved it to 8000. it would push 11-12 psi

so they cut it at 7000 and told me to get a boost controller lol

[IEVAQ8]

that dont sound right on a internal gate...................or avo setup..........my avo setup was steady on 8psi no matter what revs...........and it was on full boost at 4000rpm.................

but with the full race manifold and external gate, the exhaust gases flow too well (if that makes sens) and causes over boost.

thats the probs i was having with 9psi spring it was opening at bout 10psi and over boosting to 12psi............

so with a 4.5psi spring its opening at about 5psi and boosting safely to 7.5psi

if i got a boost controller, i wouold be able to hold off on the boost till around 5000rpm and let it coe on hard and hold steady boost at 8 or 9 or whatever i wanted to hold it at