Camshafts/gears

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Re: Camshafts/gears

Post by bjk »

Astron_Boy wrote:Totes.

You can start philosophizing Gen Y.
To be honest I don't really care for the generational thing, although it is funny to stereotype every once in a while.

Also, :thebird: I'm not going to live that one down, am I? :lol:
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Re: Camshafts/gears

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:cheeky:
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Re: Camshafts/gears

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Totes :lol:
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Re: Camshafts/gears

Post by slippercream »

Hey BJK... here's to pipe dreaming, man.
A game for people who constantly find themselves with light wallets.

One of only maybe 10 ever made? It's not a camshaft, but this was a custom grind.
Once upon a time... in 2008, I sent RPW 6G75 MIVEC heads to R&D custom camshafts that no one ever bought :? (at least, I don't think anyone did.)

But, back to the original point of this post - whether N/A or FI, the point of a custom grind camshaft should be to improve performance. Based on the info I've already seen on this forum, the camshafts may not be the bottleneck for these heads.
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Re: Camshafts/gears

Post by bjk »

Digging up some real dusty threads :lol: guess I succumbed to the lure of boost in the end haha

If I recall, I think Rob found the MIVEC cam is 300 duration stock.
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Re: Camshafts/gears

Post by slippercream »

Yeah, he told me. And that's why I think it's sufficient in stock form - until it's not enough :D Isn't that how it goes?
I revived another dead thread asking about flow numbers on the MIVEC heads. I really want to know what that looks like, because if anything, that will determine the throughput of the engine itself - moving parts aside.

The conundrum is this - we know that the factory crank can probably handle up to 500hp (as can most Cyclone engine counterparts). That can be remedied (as per the image above, which is for a 6G75). Regardless of the theoretical max, designing a system to include components that can maximize the engine to its full potential will be key. And the heads are often the bottleneck. Everything else can be fabricated.
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Re: Camshafts/gears

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Have you come across fto-007s build thread yet? Can't believe I hadn't thought to mention it yet lol. You won't find another 6A12 MIVEC with as much money spent on it, and fortunately most of the pics are hosted on the site so they're still there. Might give you some of the answers you're looking for.

https://www.ftoaustralia.com/v3/viewtop ... 41&t=24604
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Re: Camshafts/gears

Post by slippercream »

Thanks again BJK! Great reference. I see he used RPW cams, but that it wasn't a one-and-done deal. I didn't find flow numbers anywhere in the post though, and I get it. I may just have to do a tear-down and send my heads off to be tested.

I really would love to know if he even surpassed the 400hp mark. I regrettably admit to being very aware of what it's like, dumping copious amounts of money on turbocharging a factory N/A engine that wasn't built to flow boosted. I'm really kinda sullen at this point, seeing how often people have settled at the fact that the 6A12 can't push beyond 200% its factory output without so much effort. It was a struggle getting my old 3.0L 6G72 SOHC (3rd Gen Eclipse... bored out to near 3.2L, actually) to blow past 350 - and it's pretty pretty damn obvious the limitation was the heads! (Ode to the GTO of course.)

I mean, it seems the limitations of the 6A12 are pretty evident here. As much as I'd love to retain matching numbers between engine and body, it isn't just practical - it's logical - to just abandon to something like a 6A13.

Tell you what, if I weren't restoring a COTY, I would have NO QUALMS whatsoever trying to fit something else entirely under the hood. :/

4.2L 6G75-M, perhaps? :D Just teasing.
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Re: Camshafts/gears

Post by bjk »

I think 355 wheel hp was the max. Maybe it would've cracked 400 on E85 if he hadn't sold it? I think Rob's example of a (reasonably) more wallet-friendly turbo MIVEC is a good example of what the motor can do with a little persuasion :lol: Similar peak power to a 6A13 with the boost wound up on the twins, and it still revs to 8k.

I think it'll probably come down to how you want to use it, really. Boosting my FTO was basically my first real foray into "building" a car, and I did it because I liked the model and wanted it to be faster in the most expeditious way. Having now experienced what 200hp at the wheels feels like to drive, sometimes I wonder if a refreshed MIVEC would have satisfied me after all. But then I remember also that I rarely ever utilised all of the rev range (partly out of paranoia that it would spontaneously detonate, and partly because once you're there you're already over the speed limit). The extra displacement and boost means that I also get the same power at least 1500RPM sooner, and make more consistently everywhere even after the turbos have run out of puff. So for a predominantly street-driven car at legal road speeds it is great, because I get the same sensation of power without actually having to be moving faster and increasing my chance of a ticket lol.

The tradeoffs I guess are that crisp N/A response (not that the twins are at all laggy, mind), the exhaust note, MIVEC, and an 8250 rev cut. Maybe one day, as much as I love my little Protege, I'll sell it and just daily a GPX :lol:

I think the purity only matters if you want it to, and hey, the PR guys have been stuffing 6Gs into Mirages for years haha
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Re: Camshafts/gears

Post by slippercream »

Yeah, I understand. Personally, the keeping the car generationally accurate is a goal since I have other toys that already give me the oomph if I want it. To give you an example, one of these days I will be buying a shell of a current gen Mirage (Colt) just so I can take it to the dirt. I don't really care that it puts out a measly 70hp - it will do what it needs to on a rallycross track, given you're in the right class. Then get a wrecked Evo for parts, and I'm set for that additional "oomph" - without even having to up the power!

The FTO is by far the lightest car I've ever owned. And it's arguably the coolest looking. The closest to this was the 3G Eclipse, but that started out at 3,000lbs kerb. The FTO is 2,500. Same crank hp on paper, but clearly the curves are very different. Even if I dropped hardware in, the FTO'd still be lighter than an equivalent boosted Eclipse --- and there are A LOT of things that are heavy with the FTO. Boot lid alone has to be about 50 lbs at least! So, there's room for improvement in all the obvious places.

But, back to my original query - I can armchair mechanic 'til the cows come home, but it's always good to know what your limits are before you tell your builder "bank's open". Because if I shoot for, say, 350whp / 300lb-ft tq and accept that that's my ceiling - then I can go to my chassis guy and instead tell him to drop what I would normally spend on a monster turbo, methanol system, piping fab, and other go fast bits, and build me a Titanium subframe. (Just an example, of course... for effect).

You see where I'm going here? :)
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Re: Camshafts/gears

Post by vipfto »

whats with the freedom measurements?
reckon the bonnet is at least 6 hamburgers to the hot dog
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Re: Camshafts/gears

Post by spetz »

lol @ freedom measurements
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Re: Camshafts/gears

Post by slippercream »

I added a mustard catch can for effect ;)

Warms up the engine faster for quicker turbinator spool.
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Re: Camshafts/gears

Post by mezje »

vipfto wrote: Sat Jul 04, 2020 2:33 pm whats with the freedom measurements?
reckon the bonnet is at least 6 hamburgers to the hot dog
LOL
slippercream wrote: Mon Jul 06, 2020 4:53 am I added a mustard catch can for effect ;)

Warms up the engine faster for quicker turbinator spool.
Honestly mate, given you are yank maybe save some coin for when the roof of your 94 starts rusting to sh*t
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Re: Camshafts/gears

Post by slippercream »

Not sure how I should take that, but thanks I guess.

I realize people don't post a lot on the forums these days, but I'd like to think I'm not asking noob questions here.
No worries - I'll leave y'all be.
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Re: Camshafts/gears

Post by bjk »

If you weren't up to speed on that, 99% of pre-1997 FTOs are prone to rust bubbles coming through the roof due to a moisture trapping glue beneath the headliner. Only true fix is cutting it out and welding new plates in. Given your ambitions I don't think it'll be a deal breaker :lol:
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Re: Camshafts/gears

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slippercream wrote: Sat Jul 04, 2020 2:07 pm But, back to my original query - I can armchair mechanic 'til the cows come home, but it's always good to know what your limits are before you tell your builder "bank's open". Because if I shoot for, say, 350whp / 300lb-ft tq and accept that that's my ceiling - then I can go to my chassis guy and instead tell him to drop what I would normally spend on a monster turbo, methanol system, piping fab, and other go fast bits, and build me a Titanium subframe. (Just an example, of course... for effect).

You see where I'm going here? :)
RE: this. I think fto-007's build is still the best example of the ceiling for a boosted 6A12, unless you want to throw another $40k at the engine to see what it can do haha. But for the money and result, you'd be better off starting with the 6A13tt if you plan on boosting it. If you already have fast cars in the garage, untapping the potential left in the MIVEC and reducing weight where possible is probably gonna be just as enjoyable. (I vote ITBs for maximum wasteful N/A $$$ :lol: )
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Re: Camshafts/gears

Post by slippercream »

Ok, thanks for the clarification :)

It's a bit off-topic but (as you and Vectose know) I've already engaged folks to do my chassis resto. Not really worried about that part.

Now BTT, I do appreciate the input, BJK. I think the best way to put this question of head flow to rest is to get someone to cut up a set of heads, and then put some cylinders on a flowbench. I'll just leave it at that for now.

6A13... yes - that's an option. Maybe down the line and on a second FTO.

You know, the sad part about owning something so niche is that everything just gets incrementally more difficult, doing the same thing others can do so cheaply. Of course, I'm talking about the fact that we're talking about FTOs here. I read a comment just a moment ago about Evo being the benchmark for anything cost-wise. What's ironic - modifying a 6G7* has also since become so much easier and cheaper than modifying a 6A*. A lot of us have done it in NA, and with much success. And if I wanted easy, I'd just drop the spare that I have into the FTO :)

Thing is, if I wanted easy, I'd have bought a Honda. As you can see in my sig below, I'm a glutton for punishment.
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Re: Camshafts/gears

Post by supern0va »

much agreed slipper, honestly half the fun and adventure is doing things other people wont do (modifying 6A mivec etc) in a sense we are crusading our own modified car space that no one else is really in for better or worse :)
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