Gasflowed head and forced induction

[Reinhoud]

Gents, I've got a ported head on my GS, it has a pretty nice flat torque curve, but I also have a gas flowed (Brian Johnson if I'm correct) lying around.  It's a piece of art!! Very nicely done..

 

I want to take the engine apart to see if I can find what causes the vibration I have.

Now I thought to put that gasflowed head on. But this head needs some $$$ to spend on..

 

So, my question; Is there a considirable difference with a gas flowed head with forced induction?

I thought I ask before I start spending money.

 

Thanks

Edited June 4, 2021 by Reinhoud

[Gixer1460]

Simple answer - Yes! Whole basis for making power is moving air and the easier it can be done the better. An un-ported intake induces drag needing more force (boost) to overcome it ( very simplistic). So if the air path is smoother, less turbulent, more direct you will require less boost to achieve the same HP (providing the fuel is there obviously) or conversely use the same boost as before and make more power!

I've seen some of BJ's 'skulled' heads for use with TF and nitrous ProMod engines - a lot of work and engineering involved but lush!

[clivegto]

I would also say yes. I run a Rodger Upperton flowed big valve head on my setup, it makes good power with only a small turbo. 

[Arttu]

Like said above, porting works the same way on boosted engines than on NA engines. But maybe I should add a couple of things that are worth of noting with boosted engines:

• Power gains will be similar, in percentage, than on NA engines. So typically around 10% maximum. If you aren't on the limits with the charger or knock threshold you can gain the same power by relatively small boost increase. On the other hand porting may improve off-boost performance too and make the turbo to spool faster.
• If you are already on the limits of your turbo you may not gain anything with porting since the turbo can't support increased flow.

[MeanBean49]

I noticed a difference on mine too, added about 25bhp for the same boost levels throughout most of the rpm range. Its like anything, if the engine has to work less hard to do somthing, power will increase

[vizman]

Like turn a back wheel?

[Reinhoud]

Thanks guys!

 

I did read once that it wouldn't make a difference with forced induction, but I didn't think the source was reliable..

What you guys say about make it all as good as possible before boost, sounds logic.

 

I'll spend some money then

[MeanBean49]

1 hour ago, Reinhoud said:

Thanks guys!

 

I did read once that it wouldn't make a difference with forced induction, but I didn't think the source was reliable..

What you guys say about make it all as good as possible before boost, sounds logic.

 

I'll spend some money then

I heard the same, I think the logic was why put a load of money into a head for 25bhp when an extra half a psi would do the same.

To me I would rather make the extra power without putting extra load/stress on my motor

[Reinhoud]

Had a look in that (organized) mess called my shed, I have to spend quite a bit less $$$ then I thought.

I've found 3 intake valves, and the tappets I found pretty cheap on E-bay.

 

I have all I need in the other head, but I like to keep the other head assembled/complete. 

[Reinhoud]

On 6/2/2021 at 9:58 PM, MeanBean49 said:

I noticed a difference on mine too, added about 25bhp for the same boost levels throughout most of the rpm range. Its like anything, if the engine has to work less hard to do somthing, power will increase

25hp?! That's quiet a bit!! Have you riden your bike with and without a gasflowed head?

[Reinhoud]

On 6/2/2021 at 8:00 PM, Arttu said:

Like said above, porting works the same way on boosted engines than on NA engines. But maybe I should add a couple of things that are worth of noting with boosted engines:

• Power gains will be similar, in percentage, than on NA engines. So typically around 10% maximum. If you aren't on the limits with the charger or knock threshold you can gain the same power by relatively small boost increase. On the other hand porting may improve off-boost performance too and make the turbo to spool faster.
• If you are already on the limits of your turbo you may not gain anything with porting since the turbo can't support increased flow.

Not sure if mine is on the limit, my small turbo seems to keep up, doesn't seem to lose presure when the revs go up, but I don't have the guts to look on the gauge when going flat out

 

I do know that a properly gasflowed head can make quiet a difference with an N/A enine, and the GS1000 doesn't has a good stock head, just wasn't sure if it makes a difference with a gasflowed head when added boost.

The head I have on it now is quiet an improvement with stock, but the other head is something different..

 

Loose as in not tight, or lose as in lost it, wich one is OO and which is O? I never can remember...

[Reinhoud]

Arttu and G I X  E R 1460, I know you 2 have a lot of HP, I'm not trying to aim for those numbers, reasonably happy with what I have. But how did you get to those high numbers? Just a lot of boost, or did you do other modifications to get there?

Just curious.. 

Edited June 4, 2021 by Reinhoud

[MeanBean49]

14 minutes ago, Reinhoud said:

25hp?! That's quiet a bit!! Have you riden your bike with and without a gasflowed head?

Yeah,  used it for years with standard head and then a coupke of years more when I swapped to big valve ported head. Generally getting the same power top end plus better mid range and at lower boost.

A worked cylinder head will add power pretty much irrelevant of what the turbo is doing. Its a good way of getting more power when your turbo is at or close to its limit.

[Reinhoud]

8 minutes ago, MeanBean49 said:

Yeah,  used it for years with standard head and then a coupke of years more when I swapped to big valve ported head. Generally getting the same power top end plus better mid range and at lower boost.

A worked cylinder head will add power pretty much irrelevant of what the turbo is doing. Its a good way of getting more power when your turbo is at or close to its limit.

Thanks, top end is nice, but mid range is better.. 

 

I think this head I have will make a difference then, the ports are bigger and the same diameter over the whole length, also the bend before the valves are way smoother..

[MeanBean49]

2 hours ago, Reinhoud said:

Thanks, top end is nice, but mid range is better.. 

 

I think this head I have will make a difference then, the ports are bigger and the same diameter over the whole length, also the bend before the valves are way smoother..

Easiest way to see what sort of difference is to run it N/A. You know exactly what the motor is doing without any assistance

[Gixer1460]

3 hours ago, Reinhoud said:

Arttu and G I X  E R 1460, I know you 2 have a lot of HP, I'm not trying to aim for those numbers, reasonably happy with what I have. But how did you get to those high numbers? Just a lot of boost, or did you do other modifications to get there?

Just curious.. 

Ha Ha Ha ! Good question . . . . . in my case money, lots of money LOL! Mind you I didn't spend most of it, that was the guy who started and run out of money! I just put all his parts together and made them work. My engine is big - cubes help anytime! Set up as a turbo and with the boost pipe disconnected it still made around 180 rwhp - found that out when doing the mapping as a good NA fuel map (I think) is essential to put boost on top of. Apart from being enlarged, the engine is std. tuning, flowed head, bigger valves (still shim 'M' head btw!), intercooler and a one off Kroll camshaft that was ground for this engine. I will get back to this one day as there is still more power to be made.

[Arttu]

13 hours ago, Reinhoud said:

Arttu and G I X  E R 1460, I know you 2 have a lot of HP, I'm not trying to aim for those numbers, reasonably happy with what I have. But how did you get to those high numbers? Just a lot of boost, or did you do other modifications to get there?

Hmm... Well, I guess you can call 320hp with 1.1 bar boost as quite good result for a +30 year old engine construction that makes barely 100hp as stock. So here goes a short analysis.

Factors that help making good power:

• Apparently pretty efficient turbo that is well matched for this boost and power. Exhaust manifold has quite good design as well.
• 1327cc displacement. It always helps to have more cubes, at least if the rest of the parts can support.
• Proper engine management. Helps to get accurate fueling and ignition timing. Although you can probably get pretty much the same results with carbs too if you put enough effort in.
• Moderate head porting with 1mm oversize exhaust valves.
• Overall setup should be pretty well thought out. There aren't any significant bottlenecks or compromises anywhere.
• E85 fuel. Although I have got pretty similar results with normal pump gasoline too so this probably doesn't give that much extra power in my case. It's more about safety headroom.

Things that could be still improved for better power:

• Charge cooling. Currently I'm using just water injection which doesn't help too much with air temp. Proper intercooling would give some noticeable gains even at this relatively low boost level.
• Cams and head. I'm still having the stock cams and due to that the torque starts to fall down pretty steeply after 7000 rpm. If I could keep it up to the limiter the power would increase pretty significantly even without increasing boost or max rpm. More radical head porting would probably help this too.

 

[Reinhoud]

Thanks guys. 

 

 

 

[Reinhoud]

Got my bike going again, put the gasflowed head on it.

It defenitly makes a difference!! It's more aggressive, lifted the front wheel in 4th gear, and still it's not real fast

 

Haven't riden it much yet, it smokes like hell, have to fix that first.

Edited December 27, 2021 by Reinhoud