20V silvertop potential.

Jawfish
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Joined: Fri Jan 11, 2013 10:12 pm

20V silvertop potential.

Postby Jawfish » Mon Mar 23, 2020 6:26 am

Hi everyone.

I have a couple of 4AGE Silvertop lying around and I was wondering what was their power potential.
I'm thinking of using a Megasquirt II as engine managements, stock internals, some cams thinking of the Kelfords 194B 270/270 Degrees, 8.70mm/8.65mm lift. Custom 4 into 1 Exhaust.

The car is a 1300lbs lotus 7 clone used for Autocross i.e. Solo 2.. I do want to keep the VTT . Currently the engine is a 140WHP 2.0L 3TC and we are looking for another alternative.

Anybody has a similar set-up ? Anybody has some Dyno sheets,
Comments Suggestions I'm a big fan of the 4AGE and would like to switch.

Cheers,
Fred

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totta crolla
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Re: 20V silvertop potential.

Postby totta crolla » Mon Mar 23, 2020 1:46 pm

What you gain in revs you lose in low down torque compared to your 2.0
The cams you are considering are only marginally more aggressive than standard. Expect to see similar WHP figures to what you already have unless you go for a fully prepared competition engine where over 200hp is possible.

davew7
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Re: 20V silvertop potential.

Postby davew7 » Wed Mar 25, 2020 2:43 am

You are not going to gain much depending on the current diff ratio. My guess is that you will have to change to a lower diff ratio. You will probably need a 4.3 gear set, and I would also try to work in a lite Wt flywheel into your build plan. davew7

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oldeskewltoy
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Re: 20V silvertop potential.

Postby oldeskewltoy » Wed Mar 25, 2020 8:33 am

OP - do you have a dyno plot??

Also you may need to change the car some as the 4AG is a taller engine then the 3T. If you make more room, you also open up the possibility of the 7AGE (7AF block, with 4AG head)

As far as power potential for a silvertop... it is similar to the Blacktop, easy enough to make it to 140-150whp... much beyond that and you are investing $$.

As power levels go up, and you are building for more power, I would recommend a 16V head over the 20V
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

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Jawfish
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Joined: Fri Jan 11, 2013 10:12 pm

Re: 20V silvertop potential.

Postby Jawfish » Wed Mar 25, 2020 1:15 pm

Thanks,
I will have to look for the Dyno graph as it was several years ago

Heres the 3TC in our first car, no fitment issue has the pan was modified.
ImageFB_IMG_1582295201789 by jawfishracing

and in action.
ImageFB_IMG_1526389260268 by jawfishracing

I had a change of plans on the second car and decided to switch from road racing to Solo 2.
Image20200203_085221 by jawfishracing

This one was built with a 4AGE with largeport head, twin mikunis, and smallport pistons, it has a lightened flywheel and 4:30 gears. The car with its current engine will be underpowered, and I'm looking at different alternatives. One option would be to go with a totally different engine, but it has its complications. So the question is do I develop the 16V, the 20V or consider doing a 7AGE or simply join the Honda K20 camp ? I do not plan on being Nationally competive so I'm not after K20 power levels. 150-160WHP would be more than enough for me.

oldeskewltoy, i was hoping you would chime in :D , a 7AGE is something that I was considering, especially as the 1800cc engine get a 100lbs weight break. I'm currious to what the real potential, I'm following the 7AGE tread and looking for some Dyno figures but I'm not finding anything concrete.

Cheers,
Fred

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oldeskewltoy
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Re: 20V silvertop potential.

Postby oldeskewltoy » Fri Mar 27, 2020 3:29 pm

Jawfish wrote:
a 7AGE is something that I was considering, especially as the 1800cc engine get a 100lbs weight break. I'm currious to what the real potential, I'm following the 7AGE tread and looking for some Dyno figures but I'm not finding anything concrete.

Cheers,
Fred


As with a 4AG... all it takes is money. Without too much $ you should be able to make more power with a 7AG over your 3T. The limiting factor for a 7AG is the valve size... go with a big valve head, and you can easily be over 160whp.

One other option would be a stroker, that would be a compromise adding some stroke(83mm vs 77), but not as much as the 7A (85.5mm stroke). the advantage to this is you keep it inside the 4A block (smaller), the disadvantage is you don't want to twist it much about 8500.



OST-065 is going to be just a bit hairier then that... a boosted, oversize valve, stroker build for a CSR car that is now being used for hillclimbs

Image
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

Jawfish
Posts: 3
Joined: Fri Jan 11, 2013 10:12 pm

Re: 20V silvertop potential.

Postby Jawfish » Sun Mar 29, 2020 1:14 pm

I'm definetly keep an eye on OST-65.
A 160 WHP 7AGE would be great. More revs than the current 3TC and more power. Also it would keep me in my 1800 cc weight break. As the car is built from scratch in my garage dealing with a taller engine is not that complicated ;)

Thanks.

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