HP numbers

**TruJDM** · 03-04-2011, 02:22 PM

Im a little confused with most of the information i have been reading online. There are tons of threads about making over 300 HP on an rb20 ewngine and the end result is with an rb25 turbo bolted on your lucky to get 250 HP, and the only way to break 300HP is an upgraded turbo.

When my car was dyno tuned it had:
250lph fuel pump
3" exhaust with cat delete and trust down pipe
split fire coils
rb25 turbo @13 lbs
hks intake
Nisstune

My car was tuned last summer and put down 278HP literaly 15 minutes before a storm came through, so the humity was obviously very high and choking my car out.
Since then I have installed a FMIC, bought tomei pon cams and tomei gears and now im stuck with what to do with the turbo. As i stated earlier acording to what i have read i have already exceeded what the 25 turbo should be doing. so If im already at 280HP now and i have added the FMIC, cams and gears, if i steel wheel the 25 turn the boost up and add injectors and a maf would i not be up to my 350+ HP goals? (excluding obvious supporting mods head bolts, gaskets etc.)

Are people just not giving this turbo the credit it deserves? or am i just missing something here?

**nelsonmxmarc** · 03-04-2011, 02:34 PM

Yes, with steel wheels you'll be fine. I made 281 whp with the stock rb20 turbo at 15 psi last year though, on a dynapack. So... Have you considered compression numbers? You'll make more than 300 whp with those mods and a 25 turbo at 14-15 psi.
Edit; didn't realize you're on stock injectors. That's what's killing your hp numbers

Your other option is to send your turbo out for a rebuild. T03E chra with potted housings and steel wheels with a solid balance will grant you 25 psi of room. You'll end up cavitating and tiring the snails out before reaching that much boost, however with the proper insight and a good builder, you can select a variety of trims and exducer/inducer sizings to suit your sought after hp numbers..

I'm going to be running a hybrid 25 turbo this year that we've worked out.. Should see spool around 3000 (there was obviously a lot more done to the motor) and 400 whp. You'll be happy with just a small steel wheel rebuild and balance. 320 range

**Skym** · 03-05-2011, 02:09 AM

Stock RB25 turbo on stock RB20DET with adjustable camgears, fuelsystem upgrade, FMIC, retuned stock ECU, etc can produce 400hp at engine or roughly 332rwhp. But that's at 1.2kgcm2 (314rwhp) 1.5kgcm2 (332rwhp). With cams + ECU tune to suit (roughly extra 24rwhp at same boost level), 350whp should be able to be done.

If you haven't upgraded the dumppipe, you might want to, as becomes a restriction at higher boost levels.

**TruJDM** · 03-05-2011, 09:33 PM

When i first started the build it seemed like my 350hp goal would never be achieved going the 25 turbo way but now it seems fairly easy. Why do you guys suppose people quote such low numbers with this set up?

**Skym** · 03-05-2011, 11:34 PM

Some dyno's can read higher than others. Or are using US hp (DIN?) that is higher than UK hp (SAE?). Dyno is just a tuning tool and should use the same dyno to see improvements with each mod you add.

I think this is the 314rwhp (1x Japanese PS = 1x US hp) at 1.2kgcm2 dynochart on Hub Dyno with stock RB25DET turbo on RB20DET and above mods -

http://i385.photobucket.com/albums/o...912_2dyno2.jpg

I think 1.5kgcm2 is the 400hp setting and dyno only.

On racetrack (1:01 around Tsukuba racetrack) -

http://eyevio.jp/movie/228538

Because they play it safe with ECU tune, boost levels, so turbo last's the distance. But for dyno you can get away with high boost levels, as don't have weight of car putting load on engine, etc. But Hub Dyno can simulate this.

Also add engine oilcooler as high oiltemps could cause oil failure, engine failure, turbo failure.

**TruJDM** · 03-06-2011, 02:10 PM

I cant believe how fast that car was tearing up the track. My car never sees the track and i dont street race, its purely a build as a hobby so im not super concerned with the cooling aspects yet but its for sure in the works.

While i have a thread open, in terms of cam installation i have the engine maunaul in PDF and have watched videos on other cam installations and it seems very straight forward. Are there any tricks or hurdles i should expect that are particular to the rb20? and when you have the engine set to TDC the cam is keyed to match the cam gear so that they are in the correct postion with the valves right? (when the dots on the gears are in line the cams will fit in the keyed postion in the cam gear and will be in proper postion for the valves)