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Join Date: Jul 2005
Location: Atlanta
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2.8LS build

hey all, Haven't posted pics of this one yet, but it's about identical to one I built not long ago, only this one is for me as it's loading into the 74 Carrera (early RS flares) I'm rescuing. She just had a bare metal respray and of course lots of metal work hence the word 'rescue'. She was a basketcase, but lots of welding and light swearing later and she's where I want her to be. The goal here of course is a lightweight Euro-Carrera-look sleeper.


engine:
39mm intake ports, 38mm exhaust. thanks Craig! (cgarr)
65-66cc ish heads
1mm deck height
twin coil on plug
lightened crank etc
Carrillo rods
92mm 10.5:1 JE shelf pistons
7r case with all usual strengthening machine work
DC65 cam (thanks John!)
964 oil pump
Dansk full-bananas RSR rallye headers and muffler exhaust. may be a bit loud but we'll find out

AEM Infinity 6 brain is in hand but haven't needed to fiddle with that yet. Big ITB injection. Rasant is making a new full-sequential distributor sensor and crank wheel which is more accurate than the AEM hockey puck which I'm told tends to dance the signal around. It will be used once available, should be any week now....

Technical stuff:

Valve springs Craig used were from Cat Cams and installed at about 85lbs seat and 244lbs over the nose with these cams, which is still a bit stiff. I removed those and placed them in another high rev motor running a GE80 cam that needed them right away and they have been great. My company took it upon ourselves to dive deeper into the issue of valve springs to explore the issue as there really wasn't anything on the market that is of modern design. My engineer ran a stasis analysis with various cam ramp speeds, component weights, and lifts, found these engines do not need near the spring pressure some throw into these things. As most of you know many Porsche race motors ran stock springs, but cam ramp speeds were not what they are today, but still the stiffness some sell is just absurd and unnecessary. For my motor, I swapped those for new valve springs my company just had re-engineered and made in Australia which are about the same spec as the Cat Cam springs, maybe a touch stiffer over the nose. These springs will be available to everyone soon

There has been significant advances in valve springs over the past couple decades, primarily material and advances in testing, not just spintron nonsense but far more accurate stress and cycle testing against various ramp speeds. My guy in Australia is a mechanical engineer and does valve springs, and that's literally all he does. We primarily use him for making Ferrari stuff as some of you may know that's one of my professions. He's made springs for everything from 206 Dino engines to flat 12 formula 1 Ferrari engines, there is no one better and more qualified with these multi-million $$ old F1 engines. A couple companies in the EU want to take lead on distributing these but I will make sure US distributors have them as well. Craig (cgarr) has already reviewed them and given them his approval stamp. More info later.

Peak dynamic efficiency should be about 101-102% in the upper 5k rpm range meaning I'm really pushing compression ratio as I'm likely exceeding the already borderline static ratio a touch. We'll find that out too

Anyway, this motor should be good for 280 or so at the flywheel like the last one.

10k RSR tach is about done, can't go without one of those of course

Merry merry all










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Old 12-25-2017, 08:27 AM
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Considered a high tech coating for springs?

I keep hearing about some gains especially in upper rev range. I’d want to coat the rockers, cam and use modern bushings too
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Old 12-25-2017, 09:16 AM
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These are coated with something, with what I have no idea. The Cat Cams units had something on them as well.

I should add I used loctite 515 on the webs rather than 574 as sort of an experiment this time. 515 has a higher tensile strength, and if we’re using the stuff on the webs as a form of additional strength for the webs then we should at least use something a bit stronger, but not too strong.
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Old 12-25-2017, 10:05 AM
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Thanks for sharing. Can't wait to see the dyno sheet.
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Old 12-25-2017, 02:50 PM
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Finally going in this weekend. Super busy with other stuff which of course places any project of mine on hold in favor of everyone else's. No worries, getting close!

Loud pipes save lives


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Old 05-11-2018, 05:36 AM
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cool project... is your dansk straight through like the original rally banana exhaust?
Old 05-11-2018, 07:26 AM
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indeed it is
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Old 05-11-2018, 09:34 AM
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Need a sound clip of that when you get it running!
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Old 05-11-2018, 11:27 AM
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gauges came out nice. tidying up the rest soon enough

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Old 05-11-2018, 11:46 AM
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Nice motor.

Curious where you estimate peak power on rpm curve with this motor using dc65?
Old 05-11-2018, 11:49 AM
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Quote:
Originally Posted by MST0118 View Post
Nice motor.

Curious where you estimate peak power on rpm curve with this motor using dc65?

I've never set one up with this exact set up before, but I've seen a couple dc60 2.7L and 2.8L engines both good to around 7500 or so. One runs here at Road Atlanta often and it's just outstanding for that course. I expect this one to be a bit higher in the band due to much lighter rods and port sizes, so 7700? I can't suggest lighter rods enough that if one can, that's some 200g per cylinder you're dropping below stock. Other than that, a DC65 only has a degree or two more duration than a 60. We certainly will find out soon enough and I will post dyno results.
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Old 05-11-2018, 12:02 PM
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Mounted. Should have it fired soon. Will post a video
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Old 05-19-2018, 08:09 AM
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cool
Old 05-20-2018, 07:14 PM
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Stacks arrived from a place in the UK that happens to make these for Triumph throttles, came out very nice. Size are 90mm long for anyone considering. Throat diameter is 50mm. They attach via an aluminum collar with a grub screw on the throttle body, then the stack simply bolts to that. They are also making plate for the air filters. I sort of balanced them on the bodies to get an idea of what it will look like. I won't bolt them on until I have it running as they do somewhat impede reaching around in there.

AEM Infinity ECU fired right up, all sensors and fuel pump working. Been writing a base map in my spare time, quite a lot to that. For anyone considering this, I have found tuning by TPS to be best. With AEM, inputting VE is almost a pointless process until the engine is running as it is only then that AEM's software helpfully tells you 'NewVe' once the thing is actually running to target A/F ratio, then one goes in and simply alters the number. 'Accel enrichment' is actually called 'wall wetting' with AEM software and each engine cam/compression choice seems to alter the flavor of this setting.

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Last edited by lvporschepilot; 05-29-2018 at 06:37 AM..
Old 05-29-2018, 05:39 AM
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looks greta mate
Where did you get the stacks from?
I have triumph speed triple ITBs as well...
Old 05-29-2018, 08:21 PM
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I found them at danST performance engineering in the UK. His website shows he makes a set of 50mm, but I asked for a set of 90mm which I believe he has since altered his website to provide an option.
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Old 05-30-2018, 04:25 AM
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