Boosting the H22 ?

[toycar]

No, not at all.


Im not going to turn this guys thread into an arguement about engine building.



Briefly I will say this;

Length of stroke plays a key role in dwell times and piston speed. IF, and this is the big question here, IF, you are going to play with a rod/stroke ratio while building a turbo motor, you should take that into consideration.


Lower piston speeds as well as a shorter stroke allow a higher rev. This is fact.

The overall speed the engine can spin to has a huge role in how much air the engine moves, in cfm. The cfm the engine produces has a huge role in what size turbo it will power best.


If you are going through all the hassle of swapping cranks, rods and pistons for a turbo motor-it would be counterproductive to do things like swap in a longer stroke crank, or higher compression pistons.



Can you run a turbo on high compression pistons? Sure.

But it would be counterproductive to do so if you are specifically building the engine for a turbo application.

[deevergote]

To my knowledge (which is limited in comparison to both of you), the use of low-compression for turbo engines is mainly to provide a margin of safety in terms of detonation. Higher compression provides a much smaller margin of error when tuning, and can result in serious internal damage under boost if not tuned very carefully.
Modern direct injection engines use considerably higher compression ratios, due to the added precision in fueling.
If "low compression" pistons are used for anything more than that, it's news to me.

Another thing that I've always heard (again, this is merely what I've picked up over the years, and not personal experience), is that a turbo engine doesn't necessarily have to rev high. The powerband can be lower with proper turbo sizing, eliminating the need for an engine that revs to the moon. For this reason, I have always thought it silly when people want to boost an F20B "so they can rev to 8500".




Still, I firmly believe that a FWD car with too much power is pretty useless on the street, or even on the track (unless it's a dedicated race vehicle.) Putting huge power to the wheels effectively, especially on public roads, is very difficult in a fairly lightweight FWD car.
That being said, a sleeved F22A with forged internals... and stock everything else (bore size, head, camshaft...) can make more than enough power than you'd ever need on the street when used with a proper turbo setup and tune. Anything more is really just for bragging rights.

[toycar]

To my knowledge (which is limited in comparison to both of you), the use of low-compression for turbo engines is mainly to provide a margin of safety in terms of detonation. Higher compression provides a much smaller margin of error when tuning, and can result in serious internal damage under boost if not tuned very carefully.
Modern direct injection engines use considerably higher compression ratios, due to the added precision in fueling.
If "low compression" pistons are used for anything more than that, it's news to me.

Another thing that I've always heard (again, this is merely what I've picked up over the years, and not personal experience), is that a turbo engine doesn't necessarily have to rev high. The powerband can be lower with proper turbo sizing, eliminating the need for an engine that revs to the moon. For this reason, I have always thought it silly when people want to boost an F20B "so they can rev to 8500".




Still, I firmly believe that a FWD car with too much power is pretty useless on the street, or even on the track (unless it's a dedicated race vehicle.) Putting huge power to the wheels effectively, especially on public roads, is very difficult in a fairly lightweight FWD car.
That being said, a sleeved F22A with forged internals... and stock everything else (bore size, head, camshaft...) can make more than enough power than you'd ever need on the street when used with a proper turbo setup and tune. Anything more is really just for bragging rights.

Everything you said is more or less spot on.



With that in mind there are a few core reasons that what you are saying is true.


-The cfm an engine makes powers the turbine on the hotside of a turbo. One determining factors of how much air your engine is moving is the RPM it is turning at. So if you design an engine to move enough air to power your turbo at 1500 rpm's, it will. It wont spin to 8,000 RPM's though. Not going to happen. And with a turbo engine the replacement for displacement is RPM's. Managing RPM's with piston speed in mind is how you rev to 8500-10,000 rpm's.

My DSM rev's to 9,600'ish every time I take it to the strip. 280 cams(basically wide open valves) Holset hx35 turbo making 33 pounds of pressure and logging 66lbs/min.

You need the hot cam to keep the valves open so the turbo can breath. If you ran a 280 cam on a high compression motor, the cam would be too hot. The compression stroke wouldn't have valves closed long enough to let the air compress, so you would have issues with unburnt fuel and atomization.

Does this make sense? The valve timing needs of high compression and long strokes are just different than a turbo engine. Can you compromise and do both, sure, but you are taking away from both the n/a side and forced induction side of things when doing so. You cannot get ideal valve timing for a turbo engine, that is also running 12:1 compression. You'll make power but the glass ceiling is much lower. V-tec really helps with doing both, but this isn't a conversation about vtec its about turbo motors in general.


-The exhaust housing on the turbo dictates the volume of air needed to create pressure. More pressure on the hotside, the faster it spins on the compressor side. The faster the compressor wheel spins, the more air it compresses. So, if you can power the turbo you can power the turbo.

Doesn't really matter what RPM you are at, its about how much air you are moving at that RPM. If the CFM you are producing at your desired engine speed is sufficient to spin your turbo into its peak efficiency, thats all that matters.

The real question is when do you want to make that power? Figure that out, and then start building around it. People need to rev to 8500 to move enough air to power a turbo that makes 600whp on a 4cylinder engine.

This is also why 600whp Honda's are slower than 350-400whp Hondas at the track. You cannot spin to 8,000 RPM's before you launch, so generally speaking you cannot use that power on the strip. An engine that makes useable power will be much quicker off the line. 600whp on a Honda is for bragging rights and dyno queen status.

Its a 4cylinder engine.

Theres no replacement for displacement, so with turbos on 4cylinder engines it turns into a conversation about engine speed to make power. In the conversation of engine speed(rpm's) piston speed and length of stroke are very important.

Probably the most important part of the conversation aside from the valve train.


-Lower compression pistons compress less air, whichs generates less heat. Piston speed also generates heat, and this is where low compression pistons(generate less heat) paired with a shorter stroke(less piston speed, less heat) become ideal in a turbo engine. Excessive heat in the cylinder can effect fuel burn as well as play a role in detonation. As heat rises in the cylinder, so does the cylinder pressure.


Not to mention higher compression pistons need the valves closed long enough to compress the air, which is the opposite of what the turbo needs to breath.

This is where valve timing starts to become an issue. Valve timing needed for turbo vs high compression/stroker engine is just plain different. Sure you can accomplish both, especially with i-vtec engines, but it is a much more elaborate process than a typical build.

Most tuners on this site don't even degree their cam(s)


Anyways, this has obviously started to turn into a discussion about engine building and I don't want to ruine this guys thread.


Sorry op.

[deevergote]

Eh, it all applies to what he's doing, if he cares to learn from it... so it's not a useless conversation!

But yes, that all makes sense to me.

[rexload]

This is also why 600whp Honda's are slower than 350-400whp Hondas at the track.

What about all the FWD Civics and Integras that run 8 sec 1/4 mile?

[wildBill83]

What about all the FWD Civics and Integras that run 8 sec 1/4 mile?

because racecar...

You cannot drive those on the streets.

[toycar]

What about all the FWD Civics and Integras that run 8 sec 1/4 mile?

There's always an exception to any rule

Show me a specific build, and I would gladly explain what exactly they have done to make their power useable.

Things like stalled autos, nitrous off the line, co2 injection, race gas, custom tranny, twin scroll manifolds etc all help make that happen.

Give me an example, and ill happily explain it. Just make sure the build has a dyno sheet and a mod list, and I will give a thorough explanation as to how and why they are able to go that fast with the numbers they are making.


There are dsm's running 14b turbos and getting into the 10's because the power is useable not because they make so much power. It's not always about how much power you make when you are talking about how fast you can go. Its more about when you make power



Just as an example I'll talk about my dsm.



My dsm is stalled to launch at 4,000 or so rpm. I can get it to turn a bit higher than that, but you get the point.


So, when Im at the tree waiting for the lights to turn im making positive pressure. Im revving and spooling my turbo before I launch and buidling about 20psi prior to launch. I make a ton of useable power when the car is going 0mph and the power is available at launch. I spray off the line to keep the turbo spooling during the launch.


This approach has yielded me 0 extra power on the dyno but shaved 1.3 seconds off my 1/4 mile times going from manual to auto. Why?

I build more boost off the line now then I used to which has created more useable power. Not more overall power, more useable power.


Just as a quick example.





HP and TQ are maybe 60% of the equation when trying to go fast


Civics/integras that make huge power like that are slower because the power isn't always useable. I say this because there are plenty of guys that set up their cars to go fast, not just make power.


MOST people making that kind of power on a 4 cylinder are doing it for bragging rights, not to go fast. Some people make huge power to go fast in the 1/4 mile, most dont though. Most people buy a giant turbo, build an engine and call it good.

Thats why NOBODY on the top 20 list has cut a time less than 10.00 in the 1/4, but plenty of people make the power to do so. Their cars are not setup to use the power they are making until its too late.

They are setup for dyno queen bragging rights and make power at RPM speeds that you will spend nearly 0 time at during a race(1/4 mile)


So, there you go. Its not about how much power, its about when you make power when you are trying to go fast. Sure, more power always helps but it is far from the answer to going fast.


***Edit***


NWaccord is the king of the hill right now;

FIRST PLACE:
NWaccord
643whp / 529wtq .....PTE6262@30psi.....F22a1 Block/F22b DOHC
1/4 Mile = 11.33 @ 131mph
Dyno Results



643whp/529wtq and he can't cut into 10's?




See my point?

[deevergote]

What about all the FWD Civics and Integras that run 8 sec 1/4 mile?

toycar's point with that statement was to illustrate how a car that makes less power in a more immediate part of the powerband can outrun a car that makes considerably more power higher up. If you have to rev up to 8000 to make the most of your power, you're going to lose to a weaker car that's hitting peak power at 5500. Provided that weaker car can put all that power to the ground effectively... and that brings me to MY point, mentioned earlier... that too much power to the front wheels will be difficult to control, ESPECIALLY on a street car. There comes a point where horsepower ruins a car.

[98vtec]

You guys must just see shit on a complete opposite spectrum as me.

There are plenty of ways to make power count nowadays. Gear/rpm based boost, traction control. The people making big power and going nowhere, yea thats their problem.

Mean piston speeds and rod stroke dont mean a damn thing for a drag based build or a DD (which will see minimal hot time vs the amount of regular driving.)

Would i accept the argument that stroker motors require more attention to detail? Do i agree that a majority of stroker h motors that fail are lack of knowledge, attention to detail, ignorance? Yes. I would agree with that. Do i agree they fail because of rod/stroke ratio and their effect on mps? Negative.

If you want to read a good thread on this topic, search long rod vs short rod on HT.

[toycar]

There are plenty of ways to make power count nowadays. Gear/rpm based boost, traction control.



Would i accept the argument that stroker motors require more attention to detail? Do i agree that a majority of stroker h motors that fail are lack of knowledge, attention to detail, ignorance? Yes. I would agree with that. Do i agree they fail because of rod/stroke ratio and their effect on mps? Negative.

Gear and rpm based boost is your explanation or example of how people are putting power to the ground?


Lol


The next thing you say is that mean piston speed don't mean a damn thing for a drag based build or a dd. Basically ruling out piston speed and relevance to engine building all together, unles you are going to play the "well it only matters in "auto-x, F-1" card.

Lol

Nowhere in this thread did I say stroker motors fail, or that people are ignorant or that they require a greater attention to detail.

It has nothing to do with any of that.

Adding to the length of the stroke changes piston speed alot, so your maximum RPM will be lowered as well. Your RPM plays a huge role in how much air you are moving, so its not often a compromise worth making when building a turbo engine.


Im not going to lay out all the math that I just spent doing the last 20 minutes, but heres the break down;


h22 stroke, 90.7 mm. I used 90 as a round number, so please keep that in mind.

Assuming 90mm
H22 stroke mean piston speed, in meters/second at;

8,000 rpm=24.00
8,500 rpm=25.50
9,000 rpm=27.00


K24 stroke, 99 mm.

K24 stroke mean piston speed, in meters/second at;

8,000 rpm=26.40
8,500 rpm=28.05
9,000 rpm=29.70





So as you can see, piston speed on a 90mm stroke at 9,000 rpm is almost the same as a 99mm stroke at 8,000.

Im not going to figure the cfm for both engines, because there are too many variables and its honestly not worth my time. However, lets just do the math for 1,000 rpm difference in cfm for one motor.

The H22.

H22 CFM at 8,000 rpm's is 319.44. I did round off to 138 cubic inches from 137.79.

Anyways, h22 cfm at 9,000 rpm's is 359.375 cfm.


Both numbers are assuming 100% VE, but here you see a gain of 40cfm over the 1,000 rpm range. Thats more than 10% in air flow. Pair that extra air flow to a compressor map, and you'll see what 40 cfm does for you when powering a giant turbo.


If you could rev 1,000 rpm's higher to make that extra cfm and keep the same piston speeds, it would be beneficial to a turbo motor.

With a longer stroke, piston speeds are getting out of control at 8500 rpm's. F1 builders aim for mean piston speeds of 27 or 28 m/s of travel.

The fastest production vehicle piston speed is on the s2000, and its piston speeds are only 25.2 m/s.

If I remember right the fastest ever documented piston speed was 39.8 m.s and it lasted 250 miles before it burnt a pencil sized hole in the center. Honda made a v12 back in the 90's that was pretty close to this as well.


So, if you cannot see where the extra 9mm of stroke contributes to piston speed issues at a higher rpm and you cannot connect the dots between the piston speed, engine speed and CFM of the engine after all the work I have done, i cannot help you.


Im done here.


Please remember this whole discussion started with you saying "counterproductive" was a terrible choice of words.

I stand by my original statement.

[NWaccord]

***Edit***


NWaccord is the king of the hill right now;

FIRST PLACE:
NWaccord
643whp / 529wtq .....PTE6262@30psi.....F22a1 Block/F22b DOHC
1/4 Mile = 11.33 @ 131mph
Dyno Results

643whp/529wtq and he can't cut into 10's?

See my point?

I agree on what your saying, it is bout usable power if you wanna be competitive (Quicker) However I disagree on "he cant cut into 10's" with my power, the car has very good usable power. The graph clearly shows it, and the tranny backs it up. In fact its ran a 11.8 @ 15psi (430whp) and chirps 1.6-1.7 in the 60'....
Only Reason we haven't cracked 10's is do to technical problems before the race. That 11.33 was done on its "first/only" pass at full boost. I guaranteed you it will run 10's no problem. You'll see next season....

**EDIT**
The 11.33 was @ 27psi....not full

[toycar]

I agree on what your saying, it is bout usable power if you wanna be competitive (Quicker) However I disagree on "he cant cut into 10's" with my power, the car has very good usable power. The graph clearly shows it, and the tranny backs it up. In fact its ran a 11.8 @ 15psi (430whp) and chirps 1.6-1.7 in the 60'....
Only Reason we haven't cracked 10's is do to technical problems before the race. That 11.33 was done on its "first/only" pass at full boost. I guaranteed you it will run 10's no problem. You'll see next season....

**EDIT**
The 11.33 was @ 27psi....not full

Im not in any way knocking what you are doing man.

You are for sure pushing the envelope in whats going on with CB7's.


My point was the times don't support the numbers. I honestly haven't even looked at your dyno pull. Just noticed 600+whp 500+wtq and no 10's.

Im sure you will get it worked out, and I look forward to seeing 10's. I guess what I was saying was more to illustrate that its not entirely about how much power you make, but when you make it and how you use it.

I bet you feel like you could lose some power and still cut into 10's if you could get other contributing factors worked out.

You are probably one of the most ambitious people on the site with the cb chassis and in no way did I bring you into this conversation for any negative reason other than to point out that hp/tq isnt everything.

Since you are the person I brought up, would you care to comment on whats holding you back, what improvements you've made and what you are currently dealing with in terms of traction, when you make power and actually using the power you are making?



I really hope I didn't rub you wrong when I said what I said. I know you'll get into the 10's with some finess and adjusting, you are making plenty of power to do so.

I think you understand my point.



**edit**

Just at a quick glance I can tell you are setting up your car to go fast and not be a dyno queen. You are making over 300whp at 4,000rpm's and you have a very attractive torque curve.


Not the kind of person I was describing at all, and I hope you know that.


Best of luck breaking into the 10's!!

Im sure you'll get it done this season.

[Sordz]

**edit**

Just at a quick glance I can tell you are setting up your car to go fast and not be a dyno queen. You are making over 300whp at 4,000rpm's and you have a very attractive torque curve.

He's only making 160whp at 4000rpm.

To me As long as your not dropping out of boost too bad when shifting at redline its a race car not just a dyno queen.

I've watched td autowerkes's ek hatch run a 9.0 @170mph on e85 with a air to air intercooler setup and I know they have gone 8's before and they have drove that car to meets before. Yes they run large drag radials and make over 1000whp and I'm sure there not out looking to race people on the streets but they can.

No one is wrong, everyone has there opinion and can do as they wish. This is a hobby and were all out to have fun.

[toycar]

643whp 529wtq @ 30psi



I think he's turning a little more than 160@4,000 rpms

I was looking at a previous dyno sheet in his thread. Hadn't found this one yet.

Either way, hes making good power at launch rpm's. Just shy of 300whp at 4400rpm

I bet he launches around 4,000, and that is very useable power.


Good shit nwaccord.


By and far the nicest turbo cb on the site in my book.

[Sordz]

643whp 529wtq @ 30psi



I think he's turning a little more than 160@4,000 rpms

I was looking at a previous dyno sheet in his thread. Hadn't found this one yet.

Either way, hes making good power at launch rpm's. Just shy of 300whp at 4400rpm

I bet he launches around 4,000, and that is very useable power.


Good shit nwaccord.


By and far the nicest turbo cb on the site in my book.

Your a smart guy toycar, but your not reading the dyno chart correct...