scalbert

Last night I couldn't sleep so I decided to work out a few details on the blown CL-S. Actually some of this would also apply to a turbo CL also. I was curious as to some limitations and potentials of various components so some math was required. To be honest I had to resort to some reference book for some standards, but it helped as the final numbers were enlightening. I’m breaking this into two parts.

First off, I wanted to determine the limitations of the stock throttle body. I based the numbers on a stock size of 64mm and then used the potential upgraded TB through King Motorsports of 68mm. You typically want your TB sized large enough to keep the air velocities below 300 in/second. Over 300 in/sec velocities can impede flow due to unwanted resonance and turbulence.

But first you need to find the actual TB area and subtract out the interference of the throttle shaft and plate. As a rule of thumb you normally double the actual area the throttle shaft and plate take up due to the extra turbulence it creates. I made an assumption of 0.25 inch shaft diameter. Once this is determined you back track to what the assumed radius is with the obstruction accounted for. For a stock 64mm TB this is 1.089 inches and the 68mm TB would be 1.168 inches.

We also need to determine what the CFM is on this motor and at various boost levels. A stock engine at 90% VE (going on the high side and assuming headers) would move about 355 CFM at 7k revs. At 4 PSI boost this would equate to about 450 CFM and 6 PSI boost (upgraded pulley) would be about 500 CFM.

The calculation to determine the air velocity is as follows:

0.76(CFM) / R^2

Here are the results in air flow velocities:

Normally Aspirated Vehicle:
64mm: 228
68mm: 198

4 PSI Boost:
64mm: 288 (Getting close to the 300 mark!!)
68mm: 250

6 PSI Boost:
64mm: 320 (Crossed the threshold and needs some work now!!)
68mm: 278 (Close but still better than 4 PSI with the stock TB)

7.5 PSI Boost (The most you could run with this blower without spinning it too fast)
64mm: 343 (Well outside desired range!!)
68mm: 298 (Right there are the limit!!)

It does appear that with the blower the stock TB is at its limit. This would probably explain why I see the boost drop as I approach redline with the 6 PSI pulley.

So it is obvious we need a larger TB. I would love to have a 70mm TB but I want all of the items on there such as the factory IAC, etc. I need to get a TB to King Motorsports so that they can see if it can be enlarged to about 68mm. If so then this might be all we need. If not we will need to look for a custom made unit which allmotor has mentioned could be done but upwards of about $500 - $600. I may just pick up a stock unit from the dealer, ship it to King for analysis and then go from there. Maybe others might want to use this one as an exchange program to help defer the costs some??

I am RobG

how'd you come about these numbers if you dont mind me asking

SLY1TYPES

are you an engineer?

how much power increase would you get with 68mm on 6psi pulley?

I'm glad you are puting all this research into our cars everyone really appreciates it

thanks

kevin

scalbert

Do you want the long or short of it??

The short of it: it is pretty simple math just using the basics for calculating area of a circle and the area of a rectangle. The flow rate information I cheated on because I did not feel like doing the conversions on my own, CFM to inches/sec, etc.

But I can certainly lay the numbers out if you like.

scalbert

I play one at my office.

I'm not sure how much power might be found. But it could be decent; maybe 5 - 10 WHP up higher in the revs.

I am RobG

nah i trust you you're one of the more educated members of this board. You make me look stupid haha, i was just curious how you came up with it.

Nashua_Night_Hawk

It is pretty simple, on dyno as you cross the restiction point of the air flow (stock 5800 rpms, modded 6250rpms), the engine output will drop.

scalbert

The next part is something ModAddict is working on, an intercooler. I was going over some sizing requirements to tray and determine what the minimum size liquid/air IC we would need and I started with the unit Brad is using:

http://store.yahoo.com/cheapturbo/pwr6dix10le3.html

This would give an internal flow area of about 280 square inches. Which isn’t much to begin with especially compared to a decently sized air/air unit. So I had to find the equivalency conversion and it turns out to be 14:1. In others words a liquid/air unit has 14 times the heat transfer potential as does an air/air unit. But this is using straight water only. With a coolant mix the transfer becomes less effective along with the fact that the coolant heats to above ambient. So the final ratio may be closer to 8:1 with all things considered. Even so, the IC being used would be equivalent to an air/air core about 2240 square inches. It would take an air/air 3 inch thick core, 24 inches tall and 30 inches long to be about equal to what Brad is using. That is large and maybe more than what is needed but more certainly doesn’t hurt in this case as the flow loss is minimal.

In looking at this the 6 inch diameter x 6 inch length may be as much core size as what I had on my Typhoon. Plus it is a cylinder which will help reduce the flow losses. This would be about the equivalent to a 3 x 16 x 30 inch air/air IC which is still pretty large.

So now I am at a point to make a decision, which size core?? One thing I would like to know, if Brad can answer this, is if overall length is what is stated or if this is the core length. If it is the core length, what is the overall length??

I’ll be doing some measurements tonight to see what I may want to fit and what modification might be needed obviously following Brad’s lead and what he had learned so far.

scalbert

The last part still has to do with the IMRC and it’s relevance on a boosted car. The more and more I think about it, it seems like it would not be wanted. This will need to be finalized on the dyno and should be simple enough to test. But if it turns out not to be needed and should remain closed; I just wonder if we might want to consider blocking off the center chamber.

There is no need to fill that chamber if it is not being used…

PavDog

This is prob a noob question (sorry), but I'd been told that Turbo & S/C would at least partially negate the benefits of VTEC. Not sure how much I believe this since both are just pushing more fuel/air through. But is one (Turbo or S/C) "better" in the CLS? And are there any timing mods that need to be done?

Yeah the TB is kinda small.. It'd be nice if someone did a decent aftermarket one. I thought there was something in the works a while back..

scalbert

Actually the cam lobe change over enhances the forced induction aspect. With the higher lift and duration the engine can use the compressed air easier Look at the following plot from Comptech. Notice the increase in power at 5000 RPM just after the VTEC solenoid is engaged:

http://www.comptechusa.com/images/dy...cls6spd_sc.pdf

The later drop off may be two fold, the above mentioned limitation in the throttle body and the ECU pulls timing up high.

As for which is better, a turbo or SC. Without a doubt a turbo is more efficient and has greater power making potential. A these lower boost levels, if the SC is intercooled, the turbo would have a minimal advantage. As boost is increased above about 6 - 7 PSI the turbo's advantage starts growing quickly.

allmotor_2000

Let me just put it this way... my car screams from 5.8K to 7.4K or wherever the rev-limiter cuts off... there is a BIG difference with the TB. My unit is a 70mm billet TB. Unfortunately it does not have IAC capabilities... but I just set my cold-idle at 1.2K RPM and when it warms up it drops to 900RPM and that's fine with me. Keep the OEM IAC unit plugged in and you don't see a check light.

I honestly feel I would have pushed an easy 400whp at 6psi if I had my turbo kit with the current setup.

Also... the King Motorsports TB is 68mm ONLY AT THE INLET side (this applies to any TB that is bored out). Remember its tapered and the manifold-side is > 1mm smaller. My unit is 70mm on the smaller side.. approaching 71+mm on the inlet side.

Steve: I am not pitching my TB, but getting a billet TB and retaining your stock unit comes to be only a little more than having one bored by someone (say King) and purchasing another stock TB.

Nashua_Night_Hawk

I am sure with some R&D, reverse engineering, a nice tuning shop can bore the TB to 70mm including the whole tract (if possible)

scalbert

I definitely agree, which is why I put feelers out to see if anyone want to 'share' the core charge.

But since I may not be driving the car for a week or two I may just send off my stock unit and see what they can do with it. It is only $150 and that will allow us to see how much they can open it up.

If it is not enlarged anough I could probably sell the TB, recoupe some of the cost and buy one from your guy. How much was it for him to make one with the IAC intact??

scalbert

There is a limitation on the amount which can be removed before you hit the throttle plate shaft bearings.

scalbert

Never mind, I just called them and found out. The measurements shown are the core length and you need to add 3 inches onto either end for the overall length. Geez Brad, that is a lot of intercooler under that hood.

Nashua_Night_Hawk

do you need a coolant pump and front raditor for this Intercooler?

Smitty

Hmmm, very interesting... nice work Steve...

Brad, it is Friday.. did you get all your IC piping today in the mail?
Keep us posted, which I know you will...


Smitty

civic4982

When I can't sleep I just :wackit: and go to bed...

scalbert

That is correct.

On the Typhoon we would use bilge pumps as replacment circulation pumps such as the following. We could pick these up for cheap compared to the lower flow rate stock pump at $250.

http://www.iboats.com/mall/index.cgi?prod_id=4618

For the heat exchanger we would us heavy duty oil coolers in addition to the stock unit.

http://store.summitracing.com/partde...part=PRM%2D301

allmotor_2000

Above 68mm... you won't have any TB left

allmotor_2000

IAC is going to be tough... $550 I figure!

scalbert

I think I'll send mine up to King on Monday or Tuesday (overnight of course) and see what they can do with it. It may be a waste of $$ but I know I have been curious, along with others, as to how much material they can take off.

I'll mic it out before and after and let everyone know.

Ramanan, I'll let you know if I need more...

ModAddict

Smitty, I recieved the 45 degree silicone elbow yesterday and will test fit it tonight. I will try to take pics and post.

Steve, The $12 bilge pump is freekin great! In regards to the IC size itself, I should have an idea later tonight as far as the max size, but would like your opinion on the minimum size also. I have questioned all along the effeciveness of the IMRC with forced induction, I believe you're on the right track. And finally, yes, I will follow your lead on the throttle body. Let me know if I can help. I live in the winter wonderland, so I think the the IAC is a must, as is antifreeze in the IC liquid.

types1967

this this is what i like lots of love for the cl!!!!!!!!!!!!! thanx steve,mod addict,smitty,allmotor.so if i get the chip for us and scalbert does all the testing on the throttle body and mod addict gets the ic working and smitty gets the casket ready for all of us maniacs after all the horespower increase were going to have then there ya go.i would say with an intercooler 6psi pulley and bigger tb and the chip i would guess around 360-370whp holy shit.then with a 7psi pulley with the ic of course maybe 390whp bye bye cv joints lol.got to love the modding community oh and smitty i want my casket big enough for me and my cl lol

ModAddict

I think I will need to relocate the MAP sensor.

Stock blower intake elbow; http://www.photohost.org/gallery/sho...t=7&thecat=500

Turned cast elbow, with 45 degree silicone blower elbow; http://www.photohost.org/gallery/sho...t=7&thecat=500

I think a little machine work on the old MAP location will be needed to get this dent out of the silicone elbow; http://www.photohost.org/gallery/sho...t=7&thecat=500

And just for fun, my custom triple gauge pod with V1 remote below; http://www.photohost.org/gallery/sho...t=7&thecat=500

ModAddict

Steve, this size might be more realistic. What do you think?; http://store.yahoo.com/cheapturbo/pwr6diameterx6.html

typeR

what about two throttle bodies? p.s.m steve did you get my PM about the 6mt LSD it was while the server switch was going on...

ModAddict

Never mind, that's the size you ran the numbers on. I know I can fit that in there. Just a little tubing management.

I need to either relocate the MAP sensor or redo the manifold flange adaptor to spin the elbow up a bit more, wich will then require another 45 degree elbow.

Either way, it sounds like the 6"x6" IC will be more than enough.

scalbert

BTW, in reading back through my post I screwed something up. It should read a maximum of 300 ft/sec, not in/sec. I was calculating a laser measurement system on roofing material and got screwed up in my thoughts.

Sorry... :o

lou_RENAMED

wish i had a supercharger

scalbert

I should have looked at the numbers better on that pump as it is only 7.5 GPM. 10 - 12 GPM would be preferred but still can be found for under $20.

I would still like to talk to someone about the flow loss in these ICs. If it is 0.5% per linear inch, the 10 inch unit would be fine. But if it is more than 1.0% we may want to go smaller. As I can tell right now, the larger the better. But honestly, the 6 inch long unit may be enough for us. I am considering welding up a new SC outlet to allow the IC to fit better. Nothing fancy as it is below the SC and out of site. I need to get some measurements first and make some drawings.

We'll soon see about the IMRC valve. I do feel that keeping it closed does two things; negates the need for transverse filling and the worry about it operating. Plus, having had the manifold off I know an easy way we can make a plate to block off the passages into the center chamber reducing the response time and potentially giving a little more power.

I do hope the stock TB can be used and opened enough. We'll know by late next week though. I can appreciate the need for the coolant lines and IAC use in your area.

scalbert

IMO, that is a bit optimistic, but wishful thinking never hurts.

I would say that with the TB, IC and 6 PSI pulley that about 330 WHP might be achieved. With the UniChip intact another 15 WHP might be in order along. But it would allow us to go up to about 7.5 PSI boost. Which could cumulatively yield about 360 - 370 WHP.

If this car made 370 WHP and was still meeting all emissions requirements, which it should. And was still a daily driver, again, which it should. This would take it to its limits on the street. I wouldn't want anymore as the car gets a little squirrelly as it is.

scalbert

That is exactly why I was thinking about us needing some metal work for this to happen. That rubbing on the silicon line worries me a bit, not to mention the depression.

But now I see where you planned on mounting the MAP...

After looking at it again I feel we will need some new items which will include metal work. I don't see how else this cane be done including the potential for rerouting coolant lines. What kills me is the amount of room behind the elbow as it is wide open and unused.

Just a little time and patience will allow us to find the ideal solution. I'm going to look into it more tomorrow.

As for the MAP, yep I think it will need to be moved. Nothing a drill press and a couple of taps can't handle.

Nice gauges, that fuel pressure reading looks familiar. I see you were at idle with the shot taken; maybe slightly cold considering the 18 inHG vacuum and the 14.5 reading being a little rich from stoichiometric.

scalbert

Two TB's would be nice but would require significant work. Most likely more than the cost of a single custom TB.

I don't recall a PM about the 6-Speed LSD, but my memory ain't the greatest lately.

ModAddict

If I could remove an inch off the end of the blower discharge and machine a lip around the end, just to clamp the silicone elbow, I think the clearance would be good. Another way would be to cut a wedge out of the outlet and weld it back together. Can cast aluminum be welded? And yes most definatly, rerouting of coolant, vac, and maybe even fuel lines will be neccessary. I will also need to move my FMU over behind the motor where it's supposed to be.

ModAddict

The 5AT has a second throttle body for the VSA. I'll try to take some measuremens to see what size it is. Frankly I'm not sure I even need or want VSA.

scalbert

A band saw and some cutting oil and you'll be set...

Yes, you can weld cast aluminum, but it may not me pretty.

scalbert

I forgot about the obstructive VSA throttle on the automatics. That would be easy enough to remove...

ModAddict

That would be great. I wonder if I'll need a VSA simm,....