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quattrorunner 01-04-2012 09:06 AM

HP guess
I'd like to ask some of you guys your opinion on my estimated hp/torque output if I could? Had something happen to me today that got me concerned about the 915/61.

I have a 77 930 engine with around 500 miles now. Inside is sc cams, stock pump, dry film lubed cams, rockers, skirts, pins, stock 6.5/1 pistons with powercoat on top and combustion chambers. All bearings also received dry film lube treatment. Turbo is GT30r 3076 milled on the intake housing from turbokraft. Spring is .6bar but it only makes .4+ bar. I use an innovate wideband and see 2.6-2.8 afr under full boost. I have a .8 bar spring that I'm waiting to put on till I do my first valve adjust. No inter-cooler at this time, have wmi not installed. Car runs really strong and I'm thinking about 300 hp at least, it's fast. any guesses before I dyno?

full quack 01-04-2012 09:41 AM

A '77 would be a 3.0 liter right? 6.5 comp. & .4-.6 bar boost level, no intercooler, headers???

I would not think you are going to get 300 crank horsepower, maybe 250-ish at best.

But that's just my knee jerk reaction thought. Others with more practical data, should chime in here.


quattrorunner 01-04-2012 10:01 AM

Loosing traction in 2nd.
Euro headers, Maybe I'm not used to this much power but it's faster than my friends 3.6 911sc

quattrorunner 01-04-2012 11:04 AM

BTW, what should be my max rpm with above specs?
Yes 3.0 and I'm told it's good to rev the smaller turbo engine?

full quack 01-04-2012 11:13 AM

I'm guessing you have a narrow body model, hence the 915 tranny? Running kinda skinny tires?


quattrorunner 01-04-2012 11:46 AM

Exactly, I'm running 245 though. Other day I had a set of 17 borbet cup 1's which are super heavy but 9 inch and 255 rear. slower with those but still seems fast with the short ratios.

mark houghton 01-04-2012 12:10 PM

[QUOTE=quattrorunner;6472449]I use an innovate wideband and see 2.6-2.8 afr under full boost. QUOTE]

Say wha....:confused: At AFR's like those you would see a gushing stream of raw gas pouring out the exhaust tip or your engine would hydrolock. That's a ratio of 2.6 air to 1.0 of gas, when the perfect non-boost most efficient ratio is more like 14.7 air for each 1.0 of gas. (just giving you crap...if it doesn't look right, we race to be the first to criticise).

Maybe you left off a "1"...thus, you meant 12.6 - 12.8, which is a bit lean but maybe not such an issue at the low boost you're running. I wouldn't want to be that lean at .8 bar boost.

The real question is: If you paint it black, will your AFR's run lower?;) As to your main question, it's been answered.

quattrorunner 01-04-2012 12:36 PM

Yeah, I mean 12.6. OK, I'm going to dyno it and prove you all wrong:)
I'm kidding too, just really love the power levels this conversion provides. I know that this combination is capable of an easy 325hp so I can't wait to get there as "250" is really powerfull.
Outran a boxter S the other day and stayed with a V8 M3 too. I don't race, just quick pulls to check/compare.

drmatera 01-04-2012 02:22 PM

with that 3076 I would bet your close to 300 hp at the crank

JFairman 01-04-2012 02:52 PM

yeah, i'd say your guess is good with the Turbokraft massaged Garret especially if you stayed with the V8 M3 that might have upgrades.

quattrorunner 01-04-2012 08:44 PM

Yeah, well the M3 actually slowly walked but for the most part......

wjfk32 01-05-2012 06:33 AM

M3 slowly walked....

What gear were u in and what speed???

U r almost there. :) I would look into an intercooler if possible and raise boost...Check AFR'S and any little tweaks to get u more top end...THAT WILL MAKE U ALOT HAPPIER. :) :) :)

On a side note, Last weekend A SS-Chevelle was messing with me when i was just cruzin in 5th-915-at 55-60mph...I didn't want no part (my gf wants me to behave more-new years resolution)..Of course it didn't last for long...Just downshifted to 4th--(temp-34-38degrees) The chevelle was about car 2 car lengths in front..He heard me and he downshifted(very loud exhaust note)...It didn't matter walked him easily..:)..He was not happy..:( after that..Didn't come to my door anymore..


quattrorunner 01-05-2012 06:56 AM

I'm waiting till my first valve adjust/retorque post build oil change before I boost more. I got a .8 bar spring from a local Porsche shop the other day and if it's weak like they seem to be sometimes, I'll add a controller per the suggestion of Chris Carroll.
That M3 was fast, he was screwing with me for a while before(not sure why). Anyway at around 70 I shifted to fourth(915) and we went from there on the expressway. Followed to just over 100 and I'd say he very slowly walked but maybe it was reaction time ya know? Very slight. Did that a few times.

wjfk32 01-05-2012 07:13 AM

Your 3rd gear goes to 90mph+...I Think u are right there....:)

I put in an MSD6AL & Black Coil -epoxy...Rev well--pill 6000rpm..

Be careful with boost control--dial a death-- U WILL ALWAYS WANT MORE...Thats why i didn't put in my car..

quattrorunner 01-05-2012 07:21 AM

I'm probably worse than you too. Chris told me it should be I'm the engine compartment. I'm thinking electronic though so I can tie it into the WMI controller. I'd hate to blow the engine up after all the drama of building it.(first time)

wjfk32 01-05-2012 07:32 AM

I just put a 1 bar spring...I only see 1bar if the temps outside are just right..
What i see most of the time is 0.8....stock intercooler..:(

Plus i was on a budget..blah--blah-- I would love more for power..but i know the 915 is limited and i need better brakes..etc..etc..Its never ending..Hey its a weekend car, just enjoy it..

Again last week--temps were down in the 30's and i was in 5th-60+ downshifted to 4th..-floored it...The freakn revs jumped and I didn't go..:(...JEEZZZ..) Now I am a little more careful of not flooring it until and can bring it to my wrench..More money to spend..

mark houghton 01-05-2012 08:34 AM


Originally Posted by wjfk32 (Post 6474264)
...downshifted to 4th..-floored it...The freakn revs jumped and I didn't go..:(...JEEZZZ..) Now I am a little more careful of not flooring it until and can bring it to my wrench..More money to spend..

It's apparent you weren't listening to the GF again. May I recommend Kennedy Engineering as an option? Sounds like you'll be going down that path soon.

quattrorunner 01-05-2012 08:44 AM

The freakn revs jumped and I didn't go..:(...JEEZZZ..)

What clutch is in your car? Hope I don't have this same clutch. Mine is a power clutch/ sport clutch from sachs.

wjfk32 01-05-2012 10:32 AM

Yup----not listening.. :)
Will chk the clutch cable 1st and adjust if needed...If not............KEP--Will get my call.

When I did my engine in 1994..I think the disk was new and a standard pressure plate...

quattrorunner 04-14-2012 12:54 PM

Still haven't dynoed it though I have made some changes.
I've also had some issues with oil leaks, high oil temps, and rocker walking problems:eek:
So I've finally got a really nice running (cool running) engine and have installed a garettson intercooler, still using .45 boost which is still great. Have not installed my boost control or WMI yet but will soon. Car was burning toyo ra1's sized 245X16 in first and second as well as part of third at times(Morning cool temps). Then installed fikse wheels and new tires which has tamed the boiling tire tendancy to first and part of second gears and also helped me launch better(I never drop a clutch). Car hauls "A". Love it.
Anyone want to update the HP guess before I dyno?

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