So I go to the dyno a couple days ago...

[TopGunn]

And I pull out 267whp AFTER THE TUNE. WTF

The motor:

Oversized Tomei Pistons,Stock Rods,Stock Crank,270 IN/EX Tomei Cams 8.8 liftAdjustable tomei cam gears.Trust bottom mount mani w/ a Trust t67 8cm^2 housing.3 inch down pipe to 3 inch exhaust.

Ok so I need your help, I was running 23 pounds of boost (1.5bar) and these are the numbers I pulled off.

Things I've checked:

Boost leaksTiming(spark)A/F perfect.Compression is great just a hair under 150 on all 4

Should I not be making bigger numbers then this? Any ideas gurus?

Oh and I was too embarrased to keep the dyno sheet, but if you really need to see it I can email the guy to send it to me.

[fabio240]

what size injectors are you running and what are the sizes of the wheels on the turbo and what compression ratio are those pistons

[Ca_Silvia]

Post the sheet, im interested to see the top end.

Gunner who did the tuning?

[TopGunn]

800cc injectors, 12.5-11.5 across the board.

8.5 compression I do beleive on the Tomei's though Im not 100 percent sure.

Anyone?

Oh and Cam did the tuning at lightspeed. Did a great job tuning it, just making real low numbers right now?

[ca18detgabby]

yeah I wouldd like to see the curve.

that will tell alot of what to do next.

[mbmbmb23]

With those mods you should have 267 ft lbs of torque...not hp. I'm wondering if your cams/gears arent dialed in as aggressively as they could be. What octane gas are you running?

[meminto]

Have you had the cams dialed in?

I had issues with HKS 272 8.8mm cams at one stage, long story short I set the at 0,0 when they should have been dialed in...

[bentvalves]

those cams are a paired set I believe and need no cam gears to optimize the valve opening and closing events, so I dont think Id be looking at degreeing the cams.

is it an 8 port or 4 port setup, and are the butterfiles working i.e. opening?

[mbmbmb23]

those cams are a paired set I believe and need no cam gears to optimize the valve opening and closing events, so I dont think Id be looking at degreeing the cams.

is it an 8 port or 4 port setup, and are the butterfiles working i.e. opening?

Yeah.....I got some (uninstalled) 256 poncams with tomei gears....and I'm almost worried about accidentally setting the gears wrong and making less power than using the cams with stock gears.

[boost_boy]

those cams are a paired set I believe and need no cam gears to optimize the valve opening and closing events, so I dont think Id be looking at degreeing the cams.

is it an 8 port or 4 port setup, and are the butterfiles working i.e. opening?

I agree with you on this one as well.

Dee

[KEMP]

rid of butterflys right meow, you do not need those tiny air stoppers

[TopGunn]

Motors from Japan, its an 8 port head. Butterflies work you can see the rod open them when you hit the gas.

Running 91, it was having no detonation or knock on the high boost?

Im really starting to think my cams aren't dialed in, but I need the specs on the cams and I can't find them...

[mbmbmb23]

Motors from Japan, its an 8 port head. Butterflies work you can see the rod open them when you hit the gas.

Running 91, it was having no detonation or knock on the high boost?

Im really starting to think my cams aren't dialed in, but I need the specs on the cams and I can't find them...

Your best bet is to goto http://www.sxoc.com and ask around with regards to cam gears and timing with the 270's, or...have your tuner fiddle around with the gears and test out a few degrees in each direction.

[Buddyworm]

I think you need a smaller turbo Dan. The greddy T67 uses a 25G wheel. Which is huge. The CA just isn't big enough to use the compressor at its peak efficiency, which is why I think your power numbers suck even with so much boost. Even though the 25G wheel is moving a lot of volume you're not getting it anywhere near its sweet spot so it's not compressing the air efficiently and you wind up with inferior charge density.

I can't find a compressor map for a 25G but even the smaller 20G wheel, while a better fit, is still too big unless you're revving the engine to 9000rpm.

That's all bench racing though. Let's see the dyno plot.

[TopGunn]

I had that cross my mind, but I cant find a compressor map like you said, so...

[mbmbmb23]

I think you need a smaller turbo Dan. The greddy T67 uses a 25G wheel. Which is huge. The CA just isn't big enough to use the compressor at its peak efficiency, which is why I think your power numbers suck even with so much boost. Even though the 25G wheel is moving a lot of volume you're not getting it anywhere near its sweet spot so it's not compressing the air efficiently and you wind up with inferior charge density.

I can't find a compressor map for a 25G but even the smaller 20G wheel, while a better fit, is still too big unless you're revving the engine to 9000rpm.

That's all bench racing though. Let's see the dyno plot.

Upon searching google for "T67" I'm finding its a popular choice for the last gen supras...which.....means it is waaaaaay too big for the CA. Sell that thing on ebay and get something that will actually spool on your motor.

[TopGunn]

Upon searching google for "T67" I'm finding its a popular choice for the last gen supras...which.....means it is waaaaaay too big for the CA. Sell that thing on ebay and get something that will actually spool on your motor.

Don't be so quick to judge what I should and shouldn't have on my motor.

The T67 is a very broad term used because of the TD06 hotside and TD07 compressor sides. There is MULTIPLE variances you can buy of this turbo for hotside sizing.

I opted for the 8cm^2 housing, the smallest housing available, and actually has a quick spool for its size at 4000rpm.

[meminto]

Unfortunately you won't find a compressor map, greddy/trust does not release them

[Buddyworm]

It's not so much a matter of spool up but CFM. Even with a teeny, tiny turbine housing there's just no way the CA will be able to flow remotely enough CFM to allow the compressor to get into it's peak efficiency island unless you rev it really high. Which would be f***ing sweet.

[dash]

Tones old 20G setup perhaps the best street CA18 setup I've seen. Redline under 8k, exceptional tq.... No way is a 20 is too big... not even as big as a 50 trim t3/t4.

xris was unhappy with the power while using mech 270s, so he changed them. Can't recall what to, but he is happy & making power now with his 20G CA18

270s not favoured on sxoc, so I'm guessing they r even more sensitive to dial in

u sure actuator is connected to butterflys ?collapsed muffler maybe ?

[Buddyworm]

"Too big" in the sense that the turbo never reaches is peak efficiency and runs closer to the surge line up top than I think is necessary. It makes for a peakier engine than need be when you can use a 16G, run the same boost and get better map coverage than a 20G.

The bottom line for me is that one of the laggiest motors I've seen is a 2.7L RB with a 25G on it. I dunno which hotside it was running but the turbo takes forever to hit.

[KEMP]

technically if the turbo is "too big" on say 25psi, then theoretically, turning th boost down to say 15psi, would weild more power by achieving set boost quicker and holding that boost setting well in the spool of its effiecency range.

if the turbo is too bg and thats why the car made unacceptable power, then turn the boost down, and it should make the same/more power by holding a lower boost quicker and longer throught the powerband and the set boost efficenecy...this is a theory that lotd and lot of honda guys have thought and some have been proved to be correct, food for thought, not stating its a fact.

[KEMP]

jesus, this is the turbo....and even if the exhaust side is smaller causing quicker spool, does not mean it doesnt need more exhaust cfm to spool it. especially since the compressor map would be peaky, no matter the exhaust size, especially on a CA

http://www.genuineperformance....2.jpg

WOWhttp://www.genuineperformance....2.jpg

[NUT-CSE]

I am confused now...... you guys say the turbo is too big how come mobne made 497hp with his old GT35 setup then?

[dash]

Quote »can't find a compressor map for a 25G but even the smaller 20G wheel, while a better fit, is still too big unless you're revving the engine to 9000rpm[/quote]..and that is exactly why I stay away from mapsDidn't tell u how well Tones 20G CA18 ripped, under 8000rpm too.Engine dyno'd @496hp + an impressive 474 ft-lbs tq

Shooting for low boost, peak efficiency and a pk hp number is ok for some, but that 16G setup will never stand out from the crowd.A "monster" has bigger fish to fry. T67 & 270s is pretty aggressive hardware... tells me, is obviously after the "big hit" of a big boy, therefore comfortable with necessary compromises I'd think.

Quote »bottom line for me is that one of the laggiest motors I've seen is a 2.7L RB with a 25G on it. I dunno which hotside it was running but the turbo takes forever to hit.[/quote] I know of a RB25/R33 whose 25G comes in ridiculously quick, ~20psi @4400? Full ac street car with stereo. 7.3sec 1/8th. Realize how quick that is ? Pulls hella hard

[Buddyworm]

Yeah but what do those torque curves look like?

[Buddyworm]

technically if the turbo is "too big" on say 25psi, then theoretically, turning th boost down to say 15psi, would weild more power by achieving set boost quicker and holding that boost setting well in the spool of its effiecency range.

if the turbo is too bg and thats why the car made unacceptable power, then turn the boost down, and it should make the same/more power by holding a lower boost quicker and longer throught the powerband and the set boost efficenecy...this is a theory that lotd and lot of honda guys have thought and some have been proved to be correct, food for thought, not stating its a fact.

Right idea, wrong explanation, sorta. I'd wager that theoretical 25psi is just running the turbo past, or too near its choke line or the specified boost just pushes the turbo up to an innefficient point of its range.

The amount of air turbos can flow doesn't increase linearly with the speed of the impeller. Past certain rotational speeds all turbos will reach a point where any more spinning just imparts more heat and doesn't actually increase charge density. If it's spinning too slow to be efficient then you get similar results. Which explains why more boost /= more power.
Modified by Buddyworm at 8:15 PM 6/15/2009

[TopGunn]

In the back of my head Im really thinking the dyno was not giving me a right number, I'd also like to try that but there isn't any dynos in edmonton!

[ca18detgabby]

your issue is it is canada.......... move to the US and you will make more power

jk

show the dyno run. that will tell us about if the turbo is too much, not enough, or w/e.

[sjbsuperman1425]

dumb question, but are you sure it was in RWHP and not RWKW?