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Discussion Starter · #1 ·
what would you have to do to a 7a to make it a 10000rpm naturally aspirated monster? and before you say anything i know this would be more expensive than going turbo but this just sounds way cool to me. what do you think?
 

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10,000 rpm in a car that makes a little over 200 isn't that fun. Trust me I had a s2000 for a while. And that was a lot more nimble and lighter than a porky Cq.
 

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One dollar spent per RPM ought to do it. If you could get the head to flow that much air & use exotic materials for the components making up the reciprocating mass you would still have to address the lubrication needs of an engine with this potential. Then getting the transmission to shift at these engine RPMs would be another issue. You need to begin with the end in mind.
Chris
 

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not to mention no low rpm torque...

The "why question" comes to mind....

A bunch of folks have tried to build 7a strokers and spent money on porting and bigger valves...Petar Antonic went as far as ITBs for his track CQ and 034 ECU.

At the end of the day, for most of us its just alot less expensive to swap in an I5 and slap on a bigger turbo for hp and torque, and the right motronic tune or aftermarket ECU.
 

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ianCQ said:
what would you have to do to a 7a to make it a 10000rpm naturally aspirated monster? and before you say anything i know this would be more expensive than going turbo but this just sounds way cool to me. what do you think?
There was a guy several years ago on Audiworld that had a pro built 90q rally car, I remember him saying that his seriously tuned 7A put out 305hp.
N/A power is all about flow through the head and the revs to match: major cam duration like 303°, no bottom end, no idle, peaky narrow powerband up real high, you'll need very close ratios in the trans and plan to do lots of shifting!!
It'll make power, but you'll have to work very hard to get the car to move fast!
If you want N/A power, you'll have to bump up the displacement ALOT: 84mm x 100mm crank will get you 2.8L (2771), custom pistons w/sky hi comp. 13:1, E85, big cam, biggest valves you can fit along with max porting; you'll have a usable torque curve, power band and have spent $10k!!!!!
 

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before thinking that you want it, drive one first around town a little. I think that will cure you of this nonsense. hell, a factory s2000 is kinda bad enough. Not to mention your 10000rpm audi would need VERY high maintenance.
 

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Why not a supercharged 20v? If you do that, you get linear torque, a LOT less expense, and spend a crap-ton less dough. You also get free of the exhaust plumbing that comes with a turbo.

Eric
 

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DDG said:
ianCQ said:
what would you have to do to a 7a to make it a 10000rpm naturally aspirated monster? and before you say anything i know this would be more expensive than going turbo but this just sounds way cool to me. what do you think?
There was a guy several years ago on Audiworld that had a pro built 90q rally car, I remember him saying that his seriously tuned 7A put out 305hp.
N/A power is all about flow through the head and the revs to match: major cam duration like 303°, no bottom end, no idle, peaky narrow powerband up real high, you'll need very close ratios in the trans and plan to do lots of shifting!!
It'll make power, but you'll have to work very hard to get the car to move fast!
If you want N/A power, you'll have to bump up the displacement ALOT: 84mm x 100mm crank will get you 2.8L (2771), custom pistons w/sky hi comp. 13:1, E85, big cam, biggest valves you can fit along with max porting; you'll have a usable torque curve, power band and have spent $10k!!!!!
Dan,

He is just asking random question like
- 7A turbo questions
- G60 supercharger on a 7a?
- how far can you go with a 7a? 10,000rpm N/A?
 

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Discussion Starter · #10 ·
nismo said:
Why not a supercharged 20v? If you do that, you get linear torque, a LOT less expense, and spend a crap-ton less dough. You also get free of the exhaust plumbing that comes with a turbo.

Eric
supercharging was one of my initial ideas. the main problem with that is finding the right charger. eaton m90 is too big, m62 is too hard to find and rotrex is just damn expensive. plus i would want that gnarly supercharger sound which i don't think i'll get with a rotrex.
 

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varia said:
Dan,

He is just asking random question like
- 7A turbo questions
- G60 supercharger on a 7a?
- how far can you go with a 7a? 10,000rpm N/A?
Just food for thought big fella... 2.8L 5cyl!!!
Hey, I'm looking for two "1 window" 5000T distributors, what's your buddy's name who has all the VW's? I saw him at pick ur part a month ago and he said he had one.....
 

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ianCQ said:
nismo said:
Why not a supercharged 20v? If you do that, you get linear torque, a LOT less expense, and spend a crap-ton less dough. You also get free of the exhaust plumbing that comes with a turbo.

Eric
supercharging was one of my initial ideas. the main problem with that is finding the right charger. eaton m90 is too big, m62 is too hard to find and rotrex is just damn expensive. plus i would want that gnarly supercharger sound which i don't think i'll get with a rotrex.
I'd consider using either a twin-screw from Whipple (used?), or a TVS blower. The TVS1320 seems to make the Ecotec motors scream, but they aren't too small for my Buick 3800, either.

Eric
 

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Mark Wetzel owns the Group A "7A" powered car, which is a "factory built" car. It has somewhere north of 14:1 compression from what I remember. I've seen and touched the car, has a Sport head on it going from memory. I think I posted pictures of it a few years ago in a gallery on here.
 

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Put a R1 or other sport bike engine/trans in your CQ and make it work with the rear diff or something? Hiyabusi turbo 400 hp mini coopers are out there -why not a Cq?

But then you have the weight(&wait) of the CQ to deal with. 7A that acts like a sport bike engine seems a bit unpossible. A CQ w/a sport bike engine seems less unpossible.

Ok Ok OK I got it!

Ready?..........Make a fiberglass shell of a CQ, like the FG Lamborghini Diablo/Murcialago kits out there.

No- for cereal, hear me out....

Ok, so FG CQ shell, then make a tube frame outta spaceage aluminium for lyeeetness (or titanium for you Mr.Moneysack).

Then Bam $50g later you have.........uh........ya. YA! That's what you have.
 

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Alloutofdonuts said:
Put a R1 or other sport bike engine/trans in your CQ and make it work with the rear diff or something? Hiyabusi turbo 400 hp mini coopers are out there -why not a Cq?

But then you have the weight(&wait) of the CQ to deal with. 7A that acts like a sport bike engine seems a bit unpossible. A CQ w/a sport bike engine seems less unpossible.

Ok Ok OK I got it!

Ready?..........Make a fiberglass shell of a CQ, like the FG Lamborghini Diablo/Murcialago kits out there.

No- for cereal, hear me out....

Ok, so FG CQ shell, then make a tube frame outta spaceage aluminium for lyeeetness (or titanium for you Mr.Moneysack).

Then Bam $50g later you have.........uh........ya. YA! That's what you have.
:lol:
 

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Um... I daily drive a car that I run past 10k on a semi-regular basis...

I find it funny how people say "burf buh no low end" aren't considering that when you bump up the compression to suit the big cams required, low end often INCREASES. You just don't notice it because the powerband goes ballistic at higher RPM instead of falling off. S2000s, for example, feel way stronger in the 2000-3000rpm range than most 2-liter cars that weigh that much.

An analogy is when people say Diesels are "torquey". No, they are not. They make no power down low, and then they stop pulling altogether. Stick the same amount of boost on the same size gasoline engine in the same RPM range and it will make a hell of a lot more torque.

Now, that aside. Stresses on an engine go up exponentially with speed. As a certain engine guy likes to say, RPM means Ruins Peoples' Motors. You will be stressing things that you didn't even realize could ever fail. Audis are known for eating oil pumps over 8,000rpm for example. Personally I wonder if this is a function of crankshaft harmonics, and if a better damper on the front and a dual-mass flywheel (where would you FIND one??) would help. Or a shorter stroke (Italian 2-liter crank?) for a stiffer crank thanks to the increased journal overlap. Or you could just do what everyone else does and go with a dry sump system, which is getting pretty cheap nowadays - I found a 3-stage unit online for well under $500.

Making power at high RPM is really easy. Keeping it alive up there for usefully long periods of time is not.

And then, as pointed out upthread, you need a trans that will allow you to shift up there. My best theoretical shiftpoint is about 9500-9700rpm, but in the real world, I'm quicker if I shift at only 7500-8000 or so because I know the trans will usually let me shift, while a high RPM shift means it usually won't let me.
 
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