The Jim G supercharger & throttle body projects both get screwed up by a dyno
I don’t know whether to laugh or cry – the circumstances are so stupidly messed up. I have warned countless others about the dangers of depending on dyno data, but now have gotten bitten myself.
It all started just before installing the supercharger kit, when I needed a dyno baseline run (to which to compare future results) here in Austin, versus the baseline data I had from two Dynojet dynos in Atlanta. Those dynos had agreed that my then completely stock 04 SSR, except for 4.56 gearing, was making around 240 to 245 rwhp. The 4.56 gearing is significant because a numerically high axle ratio reads somewhat lower on a sweep type dyno (which the Dynojetr is), due to distorted inertia effects.
I know that virtually every dyno gives lsightly different results – sometimes more than slightly different – depending on the dyno design, calibration, and operator methodology.
I selected a local Austin shop with a great reputation – Colvin Automotive – and had its Dyno perator, Daniel, do the baseline runs. Here is where I made my first error in interpreting the results, because they seemed conveniently as expected. The Colvin dyno showed about 327 rwhp. Since that was within a couple of percentage points of the 331 rwhp that my last Atlanta run by Reese Cox at MTI Racing had shown, I figured “close enough”.
What I forgot was that Reese had done that quickie tune and dyno test in a total of 1 hour right after installing the Z06 cam, in horrid ambient conditions (95 degrees, raining, and extremely low barometric pressure), trying to get me out on the highway by 10pm - in time to make The SSR Homecoming in Michigan the next day. The SSR was definitely not performing to potential during that rushed run. Furthermore, Lyndon Wester subsequently did a complete Wester tune on it that felt even better than Reese’s. This first run at Colvin was the first dyno test since the Wester tune. I realize now that I should have paid more attention to the dyno calibration right then. Going back NOW and analyzing that Colvin baseline data, I see two things that should have set off alarm bells:
1. The rpm at which peak torque occurred was higher during the Colvin dyno run than the rpm at which peak torque occurred on the MTI dyno. Regardless of dyno calibration, torque peaks don’t move from one dyno to another. Lyndon Wester’s un-rushed tune did improve the performance of my naturally aspirated SSR.
2. The Colvin database shows that the rwhp for another totally stock LM4-engined SSR was only 228.5 rwhp STD. This is 5% to 9% lower than other dynos are reporting for the 300 crank SAE hp LM4 based SSRs.
3. 327 rwhp STD translates to about 425 crank hp STD, or about 407 crank HP SAE. This is not enough to generate the 0 to 60 times I was getting at the time (5.45 seconds with a granny start, ½ tank fuel, and 235 lb. driver).
I missed all of these clues that were there to see because the answer I got from that Colvin baseline run was the one I expected without doing any analysis. Shame on me.
Then, Randy and I installed the supercharger kit. We could not get the SSR re-dynoed right after the install, because we needed to wait almost 2 weeks for Lyndon to get and program a new PCM and ship it to me, since the tune provided by Magnacharger was not going to work because of the extensive modifications to my 04 SSR that preceded the supercharger (Supermaxx headers & hi-flow cats, custom dual exhaust, Z06 cam, etc). Magnacharger is not allowed to provide custom tunes as that violates the CARB approval under which they sell the kits.
When we finally got Lyndon’s tune, it was necessarily very conservative, since tuning a supercharged engine remotely is a challenge, and you want to approach the timing and AFR rather slowly. We did some interim dynoing at Colvin, which generated surprisingly low results: initially under 400 rwhp and improving as Lyndon slowly worked the tune, until the last run made on 4-22-06, before the new larger throttle body, gave about 414 rwhp. Despite Lyndon’s slow, conservative approach on changing timing and AFR, this seemed low to me.
Yes, I know that 414 rwhp versus 240 to 245 rwhp stock sounds like a huge improvement. But, you need to look at how we got there to understand my concerns.
Remember, we had a reliable dyno, at MTI in Atlanta, showing 331 rwhp BEFORE the supercharger kit. And remember that this number was obtained under horrid conditions that night before the run to Lansing, Michigan, and before Lyndon’s tune which raised the point of peak torque (as sign of better performance). The Colvin dyno prety much echoes that number, at 327 rwhp. Now, with the supercharger kit installed, it was delivering only 414 – 331 = 83 more rwhp. The gain realized on virtually EVERY supercharged SSR I have seen data for shows a minimum of 100 rwhp and as high as 120 rwhp, for the Magnacharger kit alone.
I did not publish these numbers on the Fanatic website, as I felt they would unfairly misrepresent both Joe’s Magnacharger kits and Lyndon’s tuning expertise. I knew something was amiss, but there were multiple possibilities:
1. The dyno had become somehow mis-calibrated between the pre-supercharger and post-supercharger runs.
2. My non-standard SSR was flowing enough air to have hit an undiagnosed “plug” (most likely candidate: the stock restrictive throttle body)
3. The Eaton MP112 supercharger was too small to flow the air volume my engine was seeking (research this issue on the Internet and you will see that the MP112 is ok for a STOCK ¾ SSR, but is indeed marginal for both stock 05/06 SSRs and a highly modified 04)
4. Lyndon was being VERY conservative on the tune (Understandable, since he knows my SSR is my daily driver, and he has told me that he will not tune it to best results until we have proven that the current tune is not adversely affected by the Austin summer heat – up to 102 degrees)
Daniel at Colvin assured me that the Colvin dyno was operating correctly (This utrned out to be wrong, but he did not know that at the time). Joe told me that the earliest relief on a larger Eaton supercharger from Magnuson was this fall. Lyndon wanted to see some dyno or datalogging results done in high ambient temperatures, which at that time had not yet arrived in Austin. So, I focused on the throttle body experiment.
Randy and I installed the 90mm throttle body, and experienced the problem that I have described in detail in other postings: Pushing the accelerator pedal to the floor causes a voltage signal in the throttle control system that the vehicle computer is not expecting, and so the computer forces the engine back to idle for safety reasons (“engine protection mode”). This meant that while my SSR ran splendidly with the new TB outside of full WOT, we could not dyno test, because that of course requires a reliable 100% WOT. So, several weeks have gone by while I have waited for a cure for this WOT problem.
Two weeks ago, Colvin made me that beautiful billet “throttle stop” for my accelerator pedal. This allows me to reliably obtain 100% WOT on the datalogger or dyno without triggering the engine protection mode. So, I did a few datatlogger runs to ensure that nothing was serious amiss, before retuning to the Colvin dyno. Those datalogger runs showed that the torque peak had again moved up, with peak torque starting around 5000 but continuing past 5500 rpm. The brake specific fuel consumption numbers showed that BSFC ws best at around 5300 to 5500 rpm. This indicated to me that the throttle body had indeed improved things again. I now have an engine with an incredibly high point of peak torque – that 5500 rpm range – before fall-off. This means GREAT breathing ability. (The point of peak torque on a stock LS2 is 4400 rpm. After supercharging, the LS2 torque peak drops into the high 3000s, because the engine can’t breathe PROPORTIONATELY well enough to maximize the contribution of the blower). I was expecting some pretty good dyno results.
In the meantime, the Colvin dyno suffered an electronic failure that put it out of commission. I had to wait several days while it was diagnosed and repaired. I asked Daniel at the time if this might affect its calibration. He initially said that it simply a replacement of a failed part, but when I questioned him further, he did more checking and said that the repair technician had indeed said that there were some issues, had installed new components, and had re-calibrated. Oh-oh.
Imagine my, and Daniel’s, surprise, when we dynoed my SSR again this weekend and got a REDUCTION in peak power.
I’m not kidding. Peak power reading went down from 414 rwhp STD to 410 rwhp STD. Daniel and I were both surprised. After all, the point of peak torque had moved UP. And, the wideband AFR machine on the dyno (which had not been involved in the dyno repair) said that the AFR had gotten LEANER – another sure sign that air flow had increased. Finally, the boost pressure was a full one psi higher than on the earlier runs. This verifies that the larger throttle body had reduced intake restriction enough for the blower to be able to generate additional boost instead of consuming part of its capacity to “suck” air through the intake.
We were both troubled about how to explain this, and I asked Daniel to send me all the data via email. He did so two hours later, but also called to tell me that he had just dynoed a stock Corvette Z06 LS7 belonging to a shop technician, right after my SSR’s run, and that my SSR produced more power than the Z06 did! The Z06 came in at 409 rwhp STD. Oh-oh. A stock LS7 Z06 makes 5050 crank HP under SAE J1349, which translates to 528 rwhp STD. Since the Z06 only comes with a manual transmission, and the driveline losses total only 13%, it SHOULD have shown 459 rwhp STD (439 SAE rwhp). If you check the various aftermarket vendor sites (Corsa, etc), you will see that 440 to 460 rwhp is what is typically reported on their “before” charts when touting the gains of their aftermarket accessories. The 409 rwhp STD is about 11% low.
Daniel then shot me another email explaining that he had just dynoed his own Corvette, and it too had mysteriously lost some of its power. He plans to dyno the shop truck next week, as a further test, as he also has previous baseline data on that truck and knows for certain that NOTHING on it has changed other than the odometer reading.
The questions I am asking now are pretty obvious ones:
When exactly did the Colvin dyno get out of sync with other dynos? Did it do it slowly before the catastrophic failure that required repair? Unfortunately, we may never know.
How much power is my SSR actually now making?
How much power did Joe’s Maganacharger kit add to my already modified SSR?
How much impact did the 90mm throttle body actually have?
I think this dyno thing just blew up BOTH my Supercharger testing program and my throttle body testing program.
The first one compares my 4-22 supercharged run to my 7-01 supercharged plus throttle body run to the Z06 LS7 run. Remember, the LS7 is stock and naturally aspirated. Imagine its performance once modded and supercharged . . .
The second graph takes a good look at the torque curve on my 7-01 run. Note that while there is a technical “peak” at 5100, that “peak” is “noise”. The actual peak is a table-flat one that runs from 5000 rpm through 5600 rpm. This is an incredible torque curve. I have never seen one like it at so high an rpm.
The third graph shows my air fuel ratio (AFR) during the run. Note that the 7-01 run is NOTABLY leaner than the pre-throttle body run. In fact, for a supercharged engine, it is plainly TOO lean. Lyndon will need to richen it, along with any timing changes he feels should be made now that we know that even 102 degree weather does not produce ANY knock retard in my SSR at WOT.
It is of course tempting to speculate.
If the Z06 LS7 should really be making 459 rwhp on a properly calibrated dyno, then my 410 rwhp becomes something like 460 rwhp. That’s AFTER:
- Driveline losses of an AUTOMATIC transmission drivetrain, which normally run 22 to 23%
- A 4.56 rear axle ratio, which produces lower sweep dyno results than a 3.73 ratio
- The power used to run the blower have been syphoned off – about 58 hp
The crank number you calculate then becomes pretty impressive. Like 651 crank hp before blower losses. Too impressive to be believable.
As it stands, if we believe the 410 rwhp, predicated upon a Z06 producing only 409 rwhp, and a stock ¾ SSR making only 228.5 rwhp, we still have 410/.775 + 58 = 587 crank hp, of which 58 is diverted to run the blower, for a net crank hp of 529.
If we believe that we should yank off the 90mm TB and go back to 414 rwhp (hey, if I believe the dyno, that’s what I should do! ), then the crank number becomes 592 minus 58 for the blower, or 534 crank after the power to run the blower is subtracted.
Remember this is all with the 4.56 ratio versus the stock 3.73.
They are all good numbers. But, being an engineer, I am sort of pissed that the untimely and undetected failure of a dynamometer deprives me of RELIABLE information that I spent lots of time and lots of money to get.
Oh and by the way, before anyone posts that I should be thankful to get these kinds of results with stock LM4 heads (smaller valves than LS2 and less efficient air flow in the heads), take note before speaking: a superhcarger tends to blow well through heads that are not idealized – that’s why I haven’t spent the money to get better ones. What IS important is valve “curtain area”. This is the circumference of the valve head multiplied by the lift. Physically, it is the cross-sectional area through which the blower must blow all of the intake air. At maximum valve lift, the curtain area on an LS2 engine intake valve is 3.27 square inches. On a STOCK LM4 engine like on my SSR, it is only 2.71 square inches. But on my specific LM4 with 02 Z06 cam, it is 3.30 square inches. On the exhaust side, my curtain area of 2.68 sq in is 6% better than the 2.53 on the LS2, AND I have the Supermaxx headers and dual exhaust. No excuse for anything but good flow.
I’m not sure how to rescue both these test programs. And right now, I’m really angry, because after all the hard work and money I have put into controlling the variables here, that dyno screw-up has wiped my data precision. I’m not angry at Colvin; how could they know? I am angry at Dynojet, who did not explain to Daniel what they had done until I pushed him for a COMPLETE answer.
I’m not sure how to proceed next and get useful data that others on the Fanatic site can reliably use.
You have a pretty good baseline at MTI in Georgia right? I would try to save the data by getting one last Dyno pull there to show at what point the overall package has changed the performance on paper. I am as upset as you are on the dyno failure. So much time and effort has gone into this build to show the exact result of all the modification.
I would also add that your SSR is running great and when compared to the other vehicles they ran, you are reassured that this is a well planned performance package.
__________________ http://www.leftcoast32.com
'07 Black TrailBlazer SS "MP122HH" MagnaCharger
'05 SSR 6 Speed 427 "MP122HH" MagnaCharger Authorized MagnaCharger Dealer/Distributor
Joe: Your idea on another MTI run is not that far fetched. I MAY be going to Michigan and Ontario this summer, and if I do, a stop at MTI in Atlanta is not outlandishly out of the way.
Jim G
Last edited by JimGnitecki : 07-04-2006 at 06:42 AM.
Sorry to hear about your troubles with the dynos. Although you may not be able to recover your baseline data, have you considered an alternative? Maybe you could enlist a few other SSR owners who have trucks that are the same as yours was in its stock configuration when first dyno tested. If those trucks are dyno'd at the compnay you're using now, you can statistically estimate what your truck's baseline was. And if you know anyone locally who had made progressive changes similar to yours, e.g., gearing, you might tabulate their results and essentially recreate a baseline as well as a comparison with your incremental changes based on statistical averages.
Snomuncher: The configuration I was running during the baseline at Colvin is as far as I know, unique: MTI Dual Shotgun exhaust, Supermaxx headers with hi-flow cats, 02 Z06 cam, and sealed air intake (not a stock feature on 04 SSRs). This makes it impossible to have a "clone" of that configuration run at Colvin.
Furthermore, it would be futile to do ANY comparisons - including pure stock 03/04s - now, as the dyno calibration was clearly changed with last week's repair (the repair technician admitted that when questioned persistently by Daniel).
The comparison to the Z06 LS7 was actually the most usable result from all this, especially since the Ls7 and my SSR were run back-to-back. Since my peak was literally 1 rwhp above the LS7, we can at least ESTIMATE the crankshaft power being delivered by my SSR as follows:
Assume that the 1 rwhp difference is insignificant since the margin of error on dynoing is larger than 1 rwhp. Then, the rear wheel power produced at peak by my SSR is equivalent to that of an LS7.
An LS7 makes 505 crank hp SAE (not STD). That translates to 505 x 1.045 = 528 crank hp STD.
But, the LS7 has a MANUAL transmission, where the drivetrain losses are typically about 13%. My SSR is an automatic, where the drivetrain losses are typically 22 to 23%. That implies my crankshaft power is more like 593 crank hp STD.
(The calculation is: 0.775 X = 0.87(528) , where "X" is my crankshaft power)
This assumes that my high stall converter is not costing me more lost power than a stock converter. You normally expect a high stall converter to convert much more of the crank power into heat (that's why the transmission temperature gauge runs higher with a high stall converter, except when the vehicle is in "converter lock-up mode" on the highway).
This also ignores the fact that my gearing is WAY numerically steeper than that of the LS7, which penalizes my SSR's dyno performance on any sweep dyno test because it results in a quicker (shorter) dyno run through the rpm range. That means that more of the power is artificially used in overcoming the entire drivetrain's moment of inertia - accelerating that drivetrain much more quickly than it would have to in a street race. In fact, the raw dyno data for the two Saturday morning runs shows that because of the big gearing difference, the LS7 had 12 seconds to go through its rpm range, while my SSR did it in 4 seconds. It would be an impossible task to calculate precisely the negative effect of that, but I do know from earlier dyno run tests in 1st, 2nd and 3rd gear at Walden Automotive in Atlanta that the 3rd gear dyno results on my SSR were quite a bit higher than the 2nd gear results.
Finally, remember that the supercharger itself is consuming at least 58 crank horsepower (that's what Eaton says it needs to drive the blower at the blower rpm when my engine is at 6200 rpm. It ignores the blower drive belt losses that come in addition to that, because we don't have a way of measuring them). So the crank horsepower is at least 592 + 58 = 650 hp before the blower takes its vig.
This sounds almost too good for this engine configuration. But, even if you assume there is something wrong with the LS7 that was dynoed, and move this entire scale down 50 or 60 hp, it's still pretty clear that this configration on a 5.3 liter really works.
In fact, that persistent torque peak, which is both
(a) at very high rpm (5000 to 5600 rpm)
and
(b) at a higher rpm than when UNsupercharged
is convincing evidence that the combination of exhaust, cam, and blower here is a particularly happy one.
The 9.2 psi peak boost is also convincing evidence that something different than what Magnuson expected is occurring here (Magnuson expects 5 to 6 psi boost in stock SSR installations).
By the way, I have now double and triple checked my blower displacement calculations, and it is pretty clear that on my specific SSR the bower SHOULD be running with a 2.8 inch pulley versus the 3.0 inch shipped with the kit for use on a stock 03/04 SSR. That 2.8 inch pulley would get the blower rpm and consequently its air throughput VOLUME (not boost, but air flow volume) to better match my engine's air flow needs. But, I hesitate to make that change since I already have 9.2 psi boost on stock (not forged) pistons and connecting rod bolts. I'm not sure I want to tempt mechanical destruction on my daily driver . . .
Replacing the stock pistons and connecting rods bolts is costly because the engine needs to come out of the vehicle to do that.
And oh yes, my SSR passed its Texas emissions test recently.
I just picked up the August 06 issue of "Chevy High Performance" magazine, and on pages 50 and 51 they summarize the "Red Dog" project they just completed.
In this project, they took a Silverado pickup with the 5.3 liter engine and did an inferior versionof what I did, except that they also replaced the heads (which gave them an extra 30 rwhp per their table).
They did the following:
Crane 1.8 to 1 rockers wich got them the expected 19 rwhp
Bassani catback exhaust and K&N intake kit got them (together) 17.5 rwhp
A Crane cam got them another 31.5 rwhp (They picked the wrong cam)
Magnaflow hi-flow cats apaprently got them another 11 rwhp
The AFR 205 cylinder heads got them 30 rwhp
and finally, the Magnacharger kit got them 112 rwhp
Their dyno indicated 237 rwhp baseline and they ended up at 457 rwhp.
Their setup is pretty inferior to mine in the following ways:
- They have only a single pipe/single muffler catback system. I have a dual exhaust that proved itself magnificently on the MTI dyno.
- No headers, where as I spent the money to get the Dynatech Supermaxx headers.
- They used a cam setup (including 1.8 rockers) that their own tuner described as the wrong choice because that cam has too much duration, and "the overlap siphons off too much cylinder pressure"). I used the highly regarded 02 Z06 cam.
- Their Magnacharger kit has the "J-tube" intake, which is very inferior to the "straight in" intake on our SSR Magnacharger kits. Their flow path is tortuous compared to ours.
The only thing they did that was "better" than on mine was they spent the money on a pair of heads that got them 30 rwhp.
Nevertheless, they ended up with 457 rwhp, despite some bad choices.
All this seems to confirm that my local dyno has a serious problem. And that maybe despite its lack of measurement help, I am indeed on the right track.
Joe, what evil thinks might happen if I swapped that 3 inch pulley for the 2.8 inch? I hesitate to do that, even though the numbers say that the engine needs more air VOLUME from the blower, because 10 or 11 psi boost sounds too high to me for cast pistons and stock connecting rod bolts. With this too-small blower, I can only get the volume needed by upping the boost pressure too much, because we are in the non-efficient range of the blower.
By the way Joe, a stock Lightning, that comes with the Eaton MP112 like our SSRs do, picks up 55 rwhp by swapping to the larger displacement Kenne Bell twin screw, with no compensating tuning even. See pages 126 and 127 of "Building 4.6 / 5.4 L Ford Horsepower on the Dyno" by Richard Holdener. Page 116 explains how a Kenne Bell-equipped GT 2-valve makes more power than an Eaton supercharged 4-valve Cobra. The combination of better thermodynamic efficiency and larger displacement is the reason. That book is an absolute treasure trove of data for us Chevy guys, despite its Ford focus.
Magnuson needs to get me an MP122, and you too Joe. Your torque peak coming in lower than both your stock engine and my engine confirms what I have been talking about: insufficient blower displacement volume for the engine air throughput required.
Jim - I am afraid that if you pulley down you will blow the rods through your oil pan at this point. I don't think you can push any more boost without doing the bottom end at this point. You are already on the edge!
I want the 122 so bad I can taste it at this point. I want to start my build on the stroker engine for the 122.
__________________ http://www.leftcoast32.com
'07 Black TrailBlazer SS "MP122HH" MagnaCharger
'05 SSR 6 Speed 427 "MP122HH" MagnaCharger Authorized MagnaCharger Dealer/Distributor
Install the smaller pulley, but lower the shift points to wherever the boost hits 9 psi.
The calculations say that the area under the curve will get appreciably larger.
That book I mentioned above by Richard Holdener devoted several CHAPTERS to dyno charts, with analysis, to supercharger dyno tests with differing pulley sizes and blower types (Eaton versus Kenne Belle), on both 2-valve and 4-valve 4.6 L Ford modulars, and is an absolute GOLD MINE of data directly applciable to our SSRs.
Youn understand my question? I am currently running 9.2 psi boost, per the datalogger. But, we only get that at the highest rpms (it's an increasiing boost curve with rpm). If we use a smaller blower and get more boost everywhere, but keep the engine rpm to no higher than whatever rpm produces 9 psi boost, where is the harm?
Jim - The engine will not last, especially if you want to continue to use it as a daily driver. More boost will not be good for a daily driver, especially with a mail order tune! The MP112 will produce more then enough volume and boost to blow your engine. I have helped to this point, I dont recommend a smaller pulley.
__________________ http://www.leftcoast32.com
'07 Black TrailBlazer SS "MP122HH" MagnaCharger
'05 SSR 6 Speed 427 "MP122HH" MagnaCharger Authorized MagnaCharger Dealer/Distributor
If you were on all Dynojet dyno's using the same software (which it appears is Winpep 7 by your graphs) then they should be comparable.
I owned a Dynojet 248C for 5 years with both Winpep 6 and Winpep 7 software. I have made well over 5 thousand pulls on this and other dynos. The very reason I bought the Dynojet at the time was it provided the most consistant and comparable numbers not only from run to run and day to day but from dyno to dyno as well. Most of the time you will see them within 1-2% of each other.
If you are talking about non-eddy current dynojets then there is no "calibration" they are simply inertia based, i.e acceleration of mass in a given time which measures HP. The typical sample rate is approx. 100 times per second.
They are calibrated from the factory by the drums actual mass down to a gram, each dyno has a specific weight along with it's serial number that is used to calibrate the software. It is not "adjustable".
There are eddy current attachments for Dynojets, these do require some periodic adjustment/calibration as do all of this type.
Also for a more accurate indication have the runs scaled using the SAE correction instead of STD, STD correction will yeild a better # most times but corrects for a more "perfect" atmosphere.
Most shops will save runs for quite a while, see if you can get the run files from the different places and have the shop you are currently using overlay the
results. Or you can go to Dynojet's website and use their runviewer:
I have run Kenne Bell superchargers for nine years. I still have a brand new 2200 unit in my workshop looking for a home! The product is great and significantly outperforms the Eaton unit. Both Kenne Bell and Whipple industries are selling these products for the late model small blocks. It would be interesting to see if anyone has looked at getting one under the hood of an SSR.
I used to run around 11-12psi on the street using the 1500 unit. I got greedy and went for a smaller pulley at the track one time. The increased boost came with a bunch of additional heat. I believe this got the supercharger out of it's optimal operating range. Sounds like you are in the same place with the Eaton. The best answer is a bigger capacity blower. The lower revolutions will generate less heat and extend the life of the unit.
If you go with a bigger blower then why not port theads and intake? These heads will only flow a certain cfm at a given valve lift. If they are stock then I would bet you will gain more hp via porting instead of turning the boost up and trying to pack air through a small hole.
This has been proven time and time agian in the turbo world bu then again us turbo guys play with more boost than most of the blower guys can dream about..
My GN ran 25lbs on pump fuel with a Pro-pain Injection befor ethe GN1's. after the good heads went on I went down to 18lbs and made more hp...
I have never seen a HIGHLY MODIFIED engine that has not had the cylinder heads or oil pan off !
__________________ 1932 Ford 2 Dr 1932 Ford Roadster 1938 Ford Deluxe 1941 Chevrolet Cab Over Engine 1947 Buick Roadmaster Conv 1959 Chev Impala 1963 Corvette Split Window 2004 SSR 2004 GMC Dually 2005 GMC Jimmy
Last I checked neither Kenne Bell nor Whipple has a supercharger for the SSR! Kenne Bell was recommended to me last year but with nothing Carb approved or otherwise I opted for the Magnacharger.
Thank-you all, guys. I appreciate the feedback and help.
I had some time ago downloaded and printed out all the material on the Kenne Bell website (one inch thick binder). Disregarding the merits of specific brands, there is no doubt that they provide a LOT of useful info on that website.
One example: Their section on their Corvette C5 kits is excellent. It actually contains multiple duyno charts which show the efefcts of changes in timing, boost, throttle body, etc. VERY useful information.
