1990 rb240sx- Gavin johnsons build thread

[Gavin Johnson]

ford shadow grey metallic.

ok, doing a bit of an upgrade. turbo is a hx35w sold my 440s and im looking for some 550s. manifold is on the car, turbo is on. just had to add the external, heres some picsps resevoir relocated away from the turbo, it boils over too much

internal wg welded shut

coolant lines are now removed

ssac manifold, had to mod it a little so the compressor housing wasnt hitting

something is missing

ext wg, not sure what brand..anyone?

top piping on to figure out where to place external

wg flange welded on

manifold, wg and turbo all on



lemme know what you guys think so far!

[rb25det250sx]

looks great so far man...yeah its obviously late now but 1200F under boost is way hot... my runs 900 underboost.. most semis wit 500+hp and 40-52 psi run 12-1500*f

[Gavin Johnson]

where is your egt sensor mounted?

[thursdaymike]

so what mounts, did you use? does your front sway bar clear?

[Gavin Johnson]

rb20 , i have washers spacing it down, but im going to remove it. i think it touches every once in a while

[thursdaymike]

did you use the stock s13 transmission mount? I'm putting a rb20 into my buddies car, buy the transmission crossmember is not lining up. i thought i read somewhere ou use s14 transmission crosmember or you had to notch out the r32 motor crossmember. how did you do yours?

[Gavin Johnson]

mine just bolted up with a 20 crossmember, at least im pretty sure it did, if not use an s13 one, im certain theyre the same though

[Carl H]

1200*F is not hot at all, its about 650*C... my car at idle will sit around 500*C on a warm day.

[SullivanRacing06]

1200f is safe under boost....

[rb25det250sx]

oh really...that seem way high to me...idk maybe im thinking of it wrong..but 500+hp and 35-42psi at 1500*f seems right..but my turbo is stock and i only run about 900*f.

[Carl H]

stock ecm also targets low 10:1 afrs under boost...

[Gavin Johnson]

where would you guys suggest putting the egt? ive seen 1600 with it where it is now but im not using that mani anymore

[Gavin Johnson]

anyone? ive searched and cant find any info.

[Gavin Johnson]

bump, anybody? i may be going in an entirely different direction with this build soon, holest, manifold, wg, may all be for sale. will post the new plan when i know for sure

[StricNyne]

tap leanesy cyc manifold runner

[Gavin Johnson]

which one is leanest?, how far from the head etc etc

[Gavin Johnson]

well, went and picked up some parts, and started putting it together didnt get much as far as pics along the way but here is some now

mods ive added so far are;-stock head gasket-arp head studs-plazmaman intake manifold-555cc tomei injectors with gtr resistor pack-garret t3/t04e 60 trim turbo-mishimoto rad-fmic-samco rad hoses-hks cam gears-new water pump-greddy timing belt, tensioner and idler

also ordering nistune today, can't wait!
Modified by Gavin Johnson at 9:04 AM 4/5/2010

[l0nestar]

Looks good man. keep it up!

[Darius]

which one is leanest?, how far from the head etc etc

Late I know, but here goes:

Cylinders 5 & 6 are typically seen as being the leanest.

Most EGT sensors are located within an inch or two of the head surface.

Seeing 1600*F is very high. Either too rich, too lean or too retarded of timing.

[Gavin Johnson]

i was told to mount it 4 inches after the turbo?

[l0nestar]

i was told to mount it 4 inches after the turbo?

Rule of thumb:6" post turbo for wbo23-4" from the head in the #6 exhaust runner.

(Being scientific, I found a nice flat spot just after the 90* bend in the runner, and drilled & tapped it. ) It wasn't scientific at all. it was just for ease and was 'close enough' .. we're not doing rocket-surgery here. I'm sure Darius or I could calculate where *exactly* to mount it, but were not working with that level of precision here.

Check with MFG for placement.

[Darius]

i was told to mount it 4 inches after the turbo?

That is too late especially in a turbo application where a substantial amount of heat is used to propel the turbine. You definitely want the EGT pre-turbo.

O2 sensors should be at least 6" downstream of the turbo as l0nestar said. I mounted mine about 3 ft downstream because it was convenient for wiring.

[flatrate]

EGT doesnt really need to be monitored with what your doing, i personally wouldnt even bother with it...

[mattblancarte]

The cam cover is looking oh so nice. Props.

[the vert]

Looks good so far. Those clear cam covers are pretty sick.

[Carl H]

and why not?

EGT doesnt really need to be monitored with what your doing, i personally wouldnt even bother with it...

agressively modified setup...big turbo...I am going to asume he's trying to make some reasonably big power on this setup.how else would you monitor ignition timing?

[Yellow4g63]

I 2nd the notion. I finally got my EGT probe for my Zetronixs for the next time I jump on the dyno to tune, I want to cover my bases and try to not melt my pistons lol.

[flatrate]

and why not?

agressively modified setup...big turbo...I am going to asume he's trying to make some reasonably big power on this setup.how else would you monitor ignition timing?

The differences ignition timing has an effect on tempature isnt going to be picked up unless the user is going to datalog all EGT readings or the tune is retarded off... its not a huge difference to see... there is no target EGT to reach... its not a diesel

Ignition timing is just a number, doesnt matter if its 10 degrees or 50, you should be watching maximum brake torque on the dyno and checking spark plugs religiously thats the only real way to see whats going on.. tuning an engine via EGT is pointless unless you have 6 EGTS and a way to log it...

Not all cylinders run at the same tempature with the same AFR and Timing either so how accurate could it be unless you had one for each cylinder...

ninja edit.. Also more likely then not EGTs are hot from lack of timing and to much fuel which isnt going to hurt the motor, maybe wear on the oil and turbo faster but its certinally not going to blow up...

Now the other way around (lots of timing and or lean mixture) will blow the motor, but you should be using other things to determine which is occuring

[Carl H]

good point but at the same time it is another very useful tuning tool...as well as yet another indicator when something is wrong.i blew the fpr vac hose off of the plenum boosting 22psi, the egt gauge was howling its warning when i knew it shouldnt have been and low and behold wideband is telling me afr is 14:1.

[flatrate]

good point but at the same time it is another very useful tuning tool...as well as yet another indicator when something is wrong.i blew the fpr vac hose off of the plenum boosting 22psi, the egt gauge was howling its warning when i knew it shouldnt have been and low and behold wideband is telling me afr is 14:1.

Funny you say that, i was going to edit my post saying that it was good for basicly what you just said..

I just dont see how you could possibly get an accurate tune with a single EGT probe and no dataloging capabilites.... it would be a slow process compared to the proven methods i have previously mentioned