scalbert

Below is the message I just sent into Comptech asking for clarification. This is not a knock on the product as there is significant power throughout the rev band. I just want to know what the max boost is stated to be.

In fact, rolling onto full throttle in 1st will result in wheel spin up to the shift. The power and smoothness is great, I just want clarification.

Or maybe I have my numbers wrong, math wrong or both...

Begin Quote:

I placed a call earlier today regarding the SC for the CL-S6 but have done some further investigation on this matter. I just recently purchased the subject kit and did the install last week. The kit was of good quality although there were two bolts missing from it which I was able to replace with others I had. I did also speak to Shad last week regarding a sound emanating from the FPR which I addressed by using foam sponge gasket material on the mounting plate.

As with any other products I purchase I always verify various aspects to them. Having owned several forced induction vehicles through the years, boost level is one area I was curious about. I was under the impression that the boost levels were in the 5.5 PSI range through various sources. However, that is not what I am measuring.

As mentioned, I called in earlier and quickly spoke to an individual who told me that the boost on the Accord was about 4.5 max and that if everything was solid and the belt was not slipping the boost is correct. This I agree with as I have installed several Eaton M90 blowers over the years and am very aware of the drive ratio to boost which I will touch on shortly.

I initially installed an Autometer boost gauge which it showed a little over 3 PSI boost, Not caring much for the accuracy of an analog gauge I brought home one of our pressure calibration systems; with the pressure module I used it has an accuracy of 0.002 PSI. That is more than adequate for this test. During testing I saw a maximum reading of 3.17 PSI. This was taken by teeing into the FPR vacuum line with hard vacuum hose to the pressure meter.

I went back and re-tensioned the SC belt to 25 lb/ft and checked for vacuum leaks by using carburetor cleaner on mating points. I also hooked up a scan tool to look at vacuum and at idle it was a solid 8 inHg; so no leaks. So without vacuum leaks and with a tight belt the boost should be limited to the drive ratio and engine displacement. Again, boost pressure was right around 3 PSI max. This got me thinking about if possibly the wrong pulleys are installed so I took out a caliper and started measuring. Below are the numbers I came up with and are estimates since all pulleys were measured on the car:

7.000 Inch, Crank Pulley
2.625 Inch, Alternator Drive (Inner) Pulley
3.000 Inch, Alternator SC (Outer) Pulley
3.750 Inch, SC Pulley

Based on the above values I would have a crank to SC drive ratio of 1:1.8667

Since the M62 blower is used, 62 cubic inches per rotation is move, it would flow 1.8667 * 62 = 116 CI per engine rotation

The engine is 3195 cc or about 194 CI. Since it is a four stroke engine that 194 CI needs to be divided by two

So per engine revolution it has the capacity to move 97 cubic inches

By taking the ratio of blower output to engine consumption, 116 / 97 = 1.20

This would indicate a twenty percent increase in boost pressure over ambient, or 0.20 * 14.7 = 2.94 PSI boost.

Now taking into account that an engine is not 100% efficient, I applied a correction factor of 0.9, 2.94 / 0.9 = 3.26 PSI boost

I ran the same number through on the smaller displacement Accord V6 and came up with uncorrected boost of 3.97 or corrected to 4.41. This is exactly where the AV6 is specified to be. I am pretty sure the crank and alternator pulleys are the same size as used on the CL-S so this does make sense.

Sorry for the long winded dialogue, I just wanted to be clear on my end. What I am curious about is if the pulleys are correct?? If so, what is the expected boost pressure from the CL-S6 system?? Or maybe my numbers above are way off…

Thanks, and I look forward to your response.

Best Regards,
Steve Calbert
scalbert@flwse.com
Director, Engineering

Zapata

LOL, I"m sure they usually don't emails like that....... good luck.

Scrib

I wish I had 1/10th the automotive knowledge Steve has...

AcurajL

I am now smarter thanks to you!

mattg

i bet they're like "who is this guy?"

typeR

i was thinking the 5.5 psi pulley was the upgrade?

Allout

Hopefully they give you a response that is more than just a "Yes".

Great analysis and well thought out. If you're lucky, they'll put you on their beta test list.

Titand19

comptech loses, hopefully they wont give you some bs email back

sidemarker

sounds like you sent them a resume

i wouldnt be surprised if they offered you a job too!!!!!

sidemarker

Loseit

iTrader: (1)

the customer service guy just shit in his pants.

Zootking

After reading that analysis Steve, Im definitely bringing my car down to you, that is if i decide to get the charger....and if you would still be able to do it

lou_RENAMED

I can just imagine everybody at Comptech gathering around Scalberts printed e-mail doing this

types1967

good luck scalbert let me know what you find

acur8ly

iTrader: (1)

I understood that like I was only 3 1/2 years old. Hope they have a real answer to give you.

xenon7

I like it ^

Comptech will have to pull all their guys together to respond.

scalbert

After thinking about this further, it might be the correct boost, which I am fine with. I just want to know for sure.

Looking at the torque curve of the Comptech dyno with the addition of the SC over a header equiped vehicle I ran the following numbers:

RPM H H&SC Perc
2600 209.9 246.8 117.58%
2800 212.3 250.9 118.18%
3000 212.3 245.8 115.78%
3200 212.9 249.5 117.19%
3400 210.7 251.6 119.41%
3600 208.5 257.4 123.45%
3800 204.6 256.4 125.32%
4000 207.8 251.7 121.13%
4200 210.8 260.1 123.39%
4400 212.1 259.7 122.44%
4600 211 257.8 122.18%
4800 210.6 258.7 122.84%
5000 212.5 272.7 128.33%
5200 212 270 127.36%
5400 210.4 266.3 126.57%
5600 210 257.1 122.43%
5800 212.6 247.9 116.60%
6000 213.6 242.1 113.34%
6200 211.2 237.5 112.45%
6400 202.7 235.5 116.18%
6600 193.2 233.8 121.01%
6800 182.6 231.3 126.67%
Average Increase 120.90%

This average increase in power would directly coorelate to the current boost level being run. So IMO, this is the correct boost level. But we shall see soon enough.

scalbert

I made the offer and certainly we could do this. Just don't ask me come July or shortly there after; I will be a bit busy during that time frame.

types1967

hey steve i sent you a pm if you could give me a call now i have to ask you something

Jens H.

Is the car faster? We just screwed one of these together for a customer and it went like a rocket after a bit of tuning with the ESM and the fuel pressure .
Jens

scalbert

The car is seriously faster, that really isn't the point. I am happy with the current performance. I just want clarification on what the boost level should be.

Based on the pulley numbers and the blower size the boost is where it should be. There is one other potential reason for lower boost, my polished intake manifold. This could lower boost a little, but at most 0.25 - 0.5 PSI.

ModAddict

Jens H,.....Are there adjusments on the ESM and if so what does it adjust. Is the FPR a rising rate regulator and is that where you adjusted the fuel pressure?

Jens H.

Mod ,in our case the ESM was slightly out of tune showing the PCM a boost signal which our PCM's are unable to deal with .ALthough it did not set a fault light it did cause a minor bucking problem .There is a set screw on the ESM that allows this to be corrected but please remember these devices are set at Comptech and should not require fiddling with .We also increased the fuel pressure somewhat as the numbers the PCM was showing us suggested it was running a bit lean .Like all heavu duty mods this one requires a bit of tunng time to get it "just so".
Jens

jimcol711

for comptech to sell a product for 4,000 dollars and then fall significantly short of its claims of the boost levels is unacceptable....i dont care how much faster it feels, what the 1/4 mile time will be, etc....its a matter of principle....if you are only offering a kit that boosts 3.0 PSI, then advertise it as such.

id ask for a percentage of my money back based on the amount of boost that you are getting that is LESS than what they advertise. Clearly, with your calculations, you have shown that the numbers you are getting are simply what the kit is capable of without a smaller pulley. Thats not fair to the customer who just dropped a significant amount of money.

how would you feel if you bought a car (any car) that was rated at 260 hp at the flywheel and you went to a dyno and it put down 130 hp....youd be pissed, and rightly so....because the car (much like this supercharger) seems to be not living up to its claims of X amount of power.

Zapata

Jim,
Why do you feel the need to over react? Steve certainly knows his stuff but i think even he will tell you that he isn't infalible. RELAAAAAAAAAAAAAAAAAAAAAAAAAAAAAX.
You end up sound like chicken little.

ModAddict

Jens,......I was suprised when you mentioned the EMS because it was my understanding it was there only to keep the PCM from reading boost and didn't think adjusting would be possible. How much did you to change the fuel preasure?

What are you using to monitor the PCM with. I assume there is nothing to edit the PCM with yet, nor any need to at these psi numbers.

THANKS!

jimcol711

youd be a liar if you said youd be comfortable finding out that you just spent 4 large and you arent getting anywhere near the boost that was advertised....maybe if you were in that position, youd understand more....when its your money that is now spent.

of course he isnt "infallible" or whatever, BUT he used a number of testing procedures and used simple (and complex!) mathematical calculations to come to all of his results....mathematics dont lie, there is no "sort-of" correct answer in mathematics, what he came up with is going to be correct with a very small margin of error (due to the fact that a car never runs the same and can change due to outside conditions)

if it were me, id be pretty pissed...if money grew on trees and my 4k just fell out of the sky, maybe i wouldnt care as much but i know i work for my money and if im spending alot of cash on something, i want to see the advertised results. period.

tankmonkey

comptech hasn't been advertising boost levels - they've been advertising an additional 54-57 hp at the wheel with the cls-6 kit.

I don't think comptech has ever officially released the boost level for their set up, although there have been numerous (more or less) educated guesses about it.

ModAddict

Jim,...Different setups will effect boost numbers. A high flowing intake and exhaust setup will yeild lower boost preasure than a more resrictive setup, but the high flow setup will out perform the other setup with higher boost preasure. Make sense?

GreenMonster

I don't remember reading any "official" comptech boost levels either.

I think what the conservative boost levels means is:

When the motor needs refreshing (150-200K miles) then lower compression pistons can be added and then the boost can be cranked up a notch

Scalbert: Thanks again for another very informative and educational post.

scalbert

As tankmonkey indicated, they haven’t advertised boost levels. They mentioned gains which could be possible with 3.5 PSI boost on this high of a CR engine.

Jim, take a deep breathe, I love the power gains so far but wanted confirmation on the expected boost levels. We’ll see what the official word is when I hear from them.

This was not meant as a blow to Comptech, the kit is great and I am pleased with my purchase. I just wanted to share my findings.

scalbert

Thank you, this is one reason why I was wondering if the porting and polishing of the intake manifold and runners might cause a lower boost reading. Less resistance can result in less boost stacking but increased power.

Jens H.

Mod ,
I work for a dealer so I can use our testers here to look a the data that the PCM sees .It is my understanding that the ESM is a generic unit that Comptech tunes for this particular installation ,Therefore since different cars have different requirements it is made to be somewaht adjustable.Yes it is designed to effectively show the PCM a full throttle acceleration and the corresponding vacuum signal but not allow a boost signal instead.We adjusted the fuel pressure so that the long term and short term fuel trim numbers were below 1.00 which in Acura speak means a richer mixture .roughly about one full turn in got us the numbers we were looking for.
Jens

allmotor_2000

First off... the FPR really shouldn't be installed blindly. You have to adjust the fuel-pressure depending on YOUR setup. It can vary from car-to-car.... even with the same mods. It is a rising-rate regulator... so there are possibility of leaning out while initially entering boost. The ESM is a generic unit designed to work with different MAP sensors (although most Honda/Acura are the same). However, it IS a clamping device (voltage-clamp) but the actualy voltage it sends the ECU can be monitored. Basically its similar to a V-AFC in that respect. Changing this voltage allows you to 'fool' the ECU. As I had suspected in Types1967's car... the ECU was seeing boost and the ESM needed to be adjusted.

Back to Steve's car: Have you tried measuring boost with the exhaust unbolted? I assume the Comptech S/C is setup such that its a cast unit from the blower to the intake-manifold... meaning you really can't have a leak there? There are numerous sources (including Comptech) that have told me its ~5psi of boost that this particuar pulley/SC unit provides.

Comptech will answer all your questions... they are good about that.

I am now really curious to see dyno #'s of the few cars that have been S/C'd. If they fall short of the 299whp # (with intake, header, exhaust) I'd have a cow.

allmotor_2000

You'd rather run a little rich than lean! I tried to maintain a 13.5 A/F ratio throughout my power-band. However with a rising-rate regulator, there is a small spike at 3000RPM when max boost kicks in... but it hits 14.0 and then 13.0 from 5000RPM onwards. Because of the excessive heat produced with boost, running rich can help curb detonation and other ill effects.

ModAddict

Thanks Jens, ...I've used "Autotap" on my 02 Camaro to monitor just about all their perameters, but they're not sure how many I will see with their import version.

With the Camaro, we were able to adjust with a MAF translator that sent modified signals to the pcm. We could adjust STFT/LTFT (usually from rich down to lean), a notch at a time, watching for knock retard, then backing up one notch. I realize this is somewhat ghetto, but the Knock sensors were very sensative and the pcm would pull timing quite effectively, and the results were consistant when checked with the wideband.

I've been told the Honda knock sensors are not very sensative, and are not used to pull timing effectively by the pcm. Do you know if that is true?

(sorry for jacking your thread Scalbert)

Jens H.

Mod ,nobody has ever really mentioned that to me before .I would guess here that since the sensors are probably the same in function as most others it is more a question of how the PCM responds in terms of how it is programmed to deal with spark knock/ping etc.
Allmotor ,per Comptech it is advised that the ESM and FPR are NOT to be adjusted as they are set at Comptech .In this case however an ESM got by that was not just so so we made a few adjustments .Like I said any mod work usually involves a bit of tuning so you quite correct .
Jens

scalbert

Ah, Autotap. I used that very much in the past with my old GTP. I now use http://www.obd-2.com but it is not as versatile as Autotap; it only shows OBDII mandated values so no KR counts, etc.

We actually do not have a MAF, it is speed density so the MAP and IAT signals are very important.

Not sure about the knock sensors as they are peizo also. Timing is pulled with knock and with higher ECT/IAT temps.

ModAddict

The J&S Safeguard supplies a different knock sensor to use with their unit for the B series motors, to monitor knock and pull timing accordingly. I guess our pcms probably don't respond to the knock, thats why this product exists.

ModAddict

I am going to get the import version "Autotap" to see what we can see. There is a 30 day money back no questions policy.

ECT temps? is that EGT? Do we have exhaust temp sensors?

Nashua_Night_Hawk

Wait a sec, Did I see a dyno of CLS-6 with headers showing 210 lbft of Torque all the way from 2600 rpm to 6200 rpms! This is for sure not stock and it has more than ICE box!