Other ADA Girdled Head

Hey Guys,

Was just thinking about ordering an ADA Girdled Head and was wondering if anyone has any instruction threads on this?

I have an 07 Superjet. Also does anyone recommend a different brand versus the ADA?
 

Proformance1

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Instructions come with it, ADA is the only way to go in most peoples opinions. Putting on the head is relatively easy, dont forget to tune it though. More compression + More fuel = Mo Power :)
 
I bought and one and installed with the instructions provided without any issues. The only thing i did that i didn't see on the instructions ( or I just missed it) was to squirt a little grease in the gaps between the long girdle bolts and crank case. Not really worried about the bolts but the threads. Don't want it to rust.
 

Matt_E

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Putting on the head is relatively easy, dont forget to tune it though. More compression + More fuel = Mo Power :)

How exactly does the addition of an ADA head require tuning? :dunno:

Added compression doesn't change the fuel requirements of the engine.

What do you do, just fatten up the jets one size?
 
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steve-uk

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I bought and one and installed with the instructions provided without any issues. The only thing i did that i didn't see on the instructions ( or I just missed it) was to squirt a little grease in the gaps between the long girdle bolts and crank case. Not really worried about the bolts but the threads. Don't want it to rust.

if your concerned about the girdle bolts/acorn nuts rusting an alternate option is the atp head, it uses all stainless fittings rather than plated fittings

it is however more expensive
 

Matt_E

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Absolutely. I have done so a few times in the past.

Tell me why increasing compression (and not changing to oxygenated race fuel or something like that) would require rejetting. I am intrigued.

When you guys rejet, what change do you see after tuning it and all that? 2.5 pts? 5 pts?


Thermodynamically speaking, the added power comes from a more efficient burn at higher compression (compression is one of very few factors determining the output power of an internal combustion engine).
This is what increases hp, not adding fuel. The air flow through the engine has not changed, only the efficiency at which fuel is burned. It doesn't need more fuel, it makes better use of the fuel that's there (hence the added power).
/nerd hat off.

Now, for real world experience:

Do you turn the screws a certain amount based on the engine stumbling? Do you turn them some amount "just because", or based on previous experience? Do you use a tach?
I'm asking because I've never felt the need to turn the screws after changing compression. No hesitation, no stumbling. However, I've never used a tach.
 
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Proformance1

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Never had to rejet, just turn the screws up a bit. If you are jetted and tuned properly and you increase compression you will require a little more fuel because of the added power.
 

D-Roc

I forgot!
i agree, but i would have said it like this. because i have increased my compression i am now able to combust a bit more fuel which will increase hp, slightly. no rejetting just adjust the high screws. having good strong spark will allow complete combustion of the added fuel.
 
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D-Roc

I forgot!
combusting more fuel will increase hp. i adjust my screws every ride this time of year as the temps change, just to keep it crisp. trying to burn too much fuel is no good either and you will loose a bit of power but keep your pistons clean.
 

Matt_E

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I ride in temps from 25 degrees air to 110 degrees air. I never touch the screws. The motor runs the same year around.

combusting more fuel will increase hp

Not really. There is an ideal mix. Going above that will decrease power.
 
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