Let's talk about VVT...

[caffeine]

Fair enough, its just I've never seen a Fiero in the 9s with a transverse setup.

Plenty of Hondas and DSMs in the 9s by comparison.

Is that guy on PFF still using stock mounting locations?

[ericjon262]

Fair enough, its just I've never seen a Fiero in the 9s with a transverse setup.

Plenty of Hondas and DSMs in the 9s by comparison.

Is that guy on PFF still using stock mounting locations?

as stock as a non stock transmission can be mounted. DH is getting close to 9's with his turbo 3800, I doubt mine will ever be in the running for 9's... and really, that's not what the discussion of VVT was about, this is more about pushing the envelope, doing what "can't" be done.

[caffeine]

I guess I'm just too practical of a person for this discussion. I just don't see any practicality in this.

[cavalier3400z]

Why not use an f40? F40, f23, hm282, hm284 have all been proven to withstand more then 400hp stock in fwd configurations. Hm282, f23, f40 I have seen behind built ls4s with only an LSD installed.


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[caffeine]

400hp could be achieved with a 3.5L though. A 3.9 with the VVT being discussed here should be capable of much more.

I've read great things about the F23 and F40 as well but besides an LSD there aren't really any upgrades available, so if you go beyond what a stock transmission is capable of, it's gonna cost big time to upgrade.

There is one 9-second Fiero I've seen a video of; its got a 3800 but its longitudinally mounted. I haven't seen any transverse 9-second Fieros. It could be a limitation of the chassis as well however.

[robertisaar]

supposedly, V8 Archie puts all of the F40s he sells through a cryotreating.... and AFAIK, the only documented failure was due to a bad measurement on some custom CV axles.

with some of the prices i've seen for cryo lately, i could definitely see it being cost-effective. with the F40, you have to either run a non-dual mass flywheel/clutch and deal with some bizzare noises or figure out how to get the dual mass setup to stand up to more torque.

[cavalier3400z]

Let's talk about VVT...

Well I believe all modern transverse 5 speed and 6 speed manual transmissions have carbon fiber syncros and the gears are put on by using liquid nitrogen to shrink the metal so there really isn't much left to do upgrade wise. I'm sure a trans shop could rebuild one for you. They are built using the same technology as most corvette and Camaro 6 speeds. As long as you get a transmission that wasn't ran low on fluid/ overheated. There should be no reason it won't last. Just check for play an put a LSD in and have fun. I'm pretty sure you will run into axle problems before trans issues. As far as the fiero chassis limiting 1/4 time I don't see that. It's a rear engine car. The car is pushed so unless you get hit in the back seat by the engine is see no issues unless some how your rip the cradle out from under the car. You would see picture of people's cars bent like a bridge if there was a structure issue.

[caffeine]

A powerful enough engine should stress any car; mid-engine doesn't really have anything to do with it IMO. Axles are another consideration. Then suspension as well. Fieros are pretty limited for aftermarket suspension when it comes to a sports car, with only one real performance option - Konis.

When you compare a Fiero to other mid-engined cars, you'll find just about everything mounts the engine longitudinally. Obviously there are other benefits to this other than transmission selection. MR2s use a similar drivetrain layout but you don't see a whole lot of super powerful MR2s either, and they have better aftermarket available.

I think if I was going to invest in something custom for Fiero performance I would start with suspension. Stock handles pretty good for an 80s car i guess but there are limited upgrades. I'm sure 88s handle better but they seem to have even less aftermarket.

I guess my point is that for an ultimate Fiero there are so many things that could be improved with custom upgrades that a one-off camshaft system would be one of the last things to do.

[cavalier3400z]

Could do a corvette suspension conversion or just put some coil overs and see how it handles. On my fiero I am just going to make some coil overs, brake upgrade maybe some strut bars/ bracing and wide tires and see how it goes.

[Guest]

I guess my point is that for an ultimate Fiero there are so many things that could be improved with custom upgrades that a one-off camshaft system would be one of the last things to do.

Forget that the thread starter owns a Fiero, forget that any of us own a particular car.

Look at the discussion for what it is, a theoretical discussion of modifying a component and related systems to change the way the engine works, for better or worse. Simple as that.

This is an interesting concept and eventually I want to play with the VCT system that is attached to these 660s. The idea of VVT in a single cam pushrod engine is very intriguing, and deserves more consideration.

My biggest concern is reliability of the cam itself. We've already seen several cam failures of the gen3 hollow cam, and can this compounding the issue. Using a later block that has the larger cam journals (3900, and what else?) can allow a stringer hollow cam to be made (thicker material, larger diameter of base cam tube, etc), to ensure reliability.

[NateD4]

I've had this same thought. The real question is why did the failures happen. On one of my LA1 3400 engines the cam came out in two pieces. The failure occurred right next to a lobe. This is most likely because the tubes are swayed around the journal blanks. For this reason I had some concern over operation above 7800 RPM. However if you know what you are doing I'd imagine you can weld the lobes to the tube, build up the journals, re-heat treat and have a cam grinder re-grind for you. This would in theory eliminate the edge that caused the 3400 cam to fail. But heat treating would be required afterword. Probably a localized anneal followed by an induction hardening and nitriding of the lobes.

Personally I think that amount or work is almost on par with a new cam blank. For this reason I've decided to get a billet cam made.

I've been getting quotes back in the $650 range for LZ cam blank with no finish grinding or heat treating. I'm using a 9310 VAR material for highest reliability. But this tacks about $150 to the price of the blank. If you go with 8620 you can get a blank for around $500

If I get enough interest I'd be interested in a group buy.


The real question is what are your goals, reliability needs and do they justify the cost of a custom cam.

[ericjon262]

The real question is what are your goals, reliability needs and do they justify the cost of a custom cam.

I'd like to see pancake flat torque curve.



the theoretical engine I made in DD shows a very flat torque curve. I'm sure I could pick up some more bottom end by reducing the duration, either way, the DD motor isn't really all that close, the flow data for the heads was for my 3500 heads, not 3900 heads, and it's a 3.5 not a 3.9 too.

I think if I build this, it will go in my RWD cavalier project I have yet to start.

[NateD4]

Does DD now have VVT capability? The copy I used 10 years ago didn't. If it doesn't you'd have to create graphs for ever degree to half degree and compare each RPM point to find the most optimum cam angle.

If I was doing it I'd record each dyno data set in excel and then find the max torque for each rpm.... Then compile those together and plot the resulting torque curve as well as the rpm vs timing curve.

[ericjon262]

Does DD now have VVT capability? The copy I used 10 years ago didn't. If it doesn't you'd have to create graphs for ever degree to half degree and compare each RPM point to find the most optimum cam angle.

If I was doing it I'd record each dyno data set in excel and then find the max torque for each rpm.... Then compile those together and plot the resulting torque curve as well as the rpm vs timing curve.

it doesn't, but what I did, was make multiples of the same engine, except with different timing, and then overlaid them.