For those who might have missed it, I posted this information a day or so ago about my recent chassis dyno results from a relatively mild 383 combination....
----------------------------------------------------------
Well I finally finished the install of the 383 that I shared some engine dyno results with you guys awhile back. It was impressive on the engine dyno and by the looks of today’s results just as impressive sitting between the fender wells of my C5 project car. Without a whole lot of time to tune and dial her in (my 346 combination came together and stages and I had logged some serious dyno time on that package), she put up 535 HP / 474 Ft/lbs (thru a 4.10 ring and pinion I might add).
To say I’m pretty jazzed about it would be an understatement….big numbers for a small displacement stroker that is a relatively mild combination. Not to mention if I really had the time, I would bet anything there is a 540/480 number in this combo….I will continue to refine this package and keep you guys abreast of my progress.
Just to quickly refresh your memory, this 383 consists of the following:
A shortblock “kit” provided by Scott Shafiroff Racing Engines (basically a balanced rotating assembly which consisted of an Eagle 4’ crank, Callies “Comp Star” rods, Mahle -7 cc dish pistons, and a fully machined/honed new aluminum LS1 block).
I blueprinted and assembled the engine personally. I did opt to change out the rings to a set of Total seal gapless top, which I feel added nicely to the overall package and results.
Other key components installed are:
ATI Dampener (only 10% underdrive)
QTP High volume pump (which I ported for better efficiency)
QTP 2 piece billet cover (priceless for cam swaps on the engine dyno)
Mezzeire electric water pump
Comp Cam’s custom grind solid mechanical street roller (242/248 .650 ish lift)
(Acts similar to a street friendly 234/240 hyd. grind....idles @ 900 with slight chop)
AFR 225 heads (PN 1630) milled to 65 cc’s (NOTE: Final CR only 11.0 to one!)
Crane Cams brand new “composite bearing” 1.7 shaft rockers (no needle bearings)
Ported FAST 90 mm Intake / NW 90 mm TB
LG “Pro Long tube” 1.75 inch headers
Random Technologies 3” high flow Cats (Yes…this power was made thru the cats)
Z06 Titanium mufflers with custom “bypass” that I fabricated using QTP electric cut-outs
(Note: thru the Z06 mufflers our best run of the day was 530 RWHP….impressive
considering how stealthy and quiet the car is with the cut-outs closed)
Note that the car was ran on the dyno today (and always) with heavier than stock Wilwood 13" rear rotors (which would hurt the #'s a little), and in full street trim....every belt connected and the exhaust exiting the rear of the car even with the cut-out (muffler by-pass) open. There were zero dyno tricks or BS used to achieve these numbers. Also, as most of the locals here know, Andy's dyno is known to be a little "stingy" with the numbers....
Speaking of which, I would also like to thank Andy at A&A Corvette for the use of his facility, dyno, and favorite tuner Charlie (who is also a personal friend of mine)….Charlie gave up watching the Super Bowl because he knew how anxious I was to get this car on the rollers. Also of noteworthy importance here is that fact that Charlie tuned my car with speed density (no MAF) and although we both agree it needs a little more time “finessing” the drivability part of the equation, from 2K to redline it’s smooth, crisp, and powerful.
I am going to edit this post shortly to include two short videos taken today….one of them showing a couple of runs on the chassis dyno (not the best run of the day however), and the other a little footage of the car grabbing a few gears on the street. Note that traction is non existent in first gear (totally peddling it), barely existent in second (note the “lift” of throttle trying to get it to hook up), and finally getting some legs underneath her in 3rd and 4th. The car feels awesome…..can’t wait to get her to the track!
Actual dyno gragh can be seen a few posts down....(thanks Charlie!)
Also here is a link to the original thread I started detailing this engine in various configurations on the engine dyno....Its informative but very long
-----------------------------------------------------------
The link to the vids wont work on this site (Im working on it) but here is a link to my original post where the video links are functional... http://www.ls1tech.com/forums/showth...=449104&page=1
Great numbers Tony and it look strong as well. Thanks for sharing this with us. Please keep us up to date on you progress.
Do you think your ported manifold will work with stock intake port opening measurements?
D.J.
Thanks...
The reality is I live for this kind of stuff anyway. Im obviously very pleased with the results in hand already but have a sneaking suspicion that some additional time tuning/tweaking will yeild 54X / 48X and Im going to do my best to get there. I might add a vacuum pump to this combination and who knows with a little luck I might see a hail mary 550 run out of this little stroker. That would certainly be insane.
Anyway, my ported intakes are usually 1.080" - 1.090" in width and about the same height as stock. I think a stock port is pretty close to that width (around 1.050 I think)....a very small lip is really not a big deal anyway (less than .030 preferably). There is very little air flowing against the walls of the port....its called a boundary layer and if you probe the port you will find that most of the air is away from the wall and traveling in the center (except the short side of an intake and the long side of an exhaust port....very high speed air can be found there).
How's the torque down low? One of my pet pieves is looking at dyno graphs that start at 3000 RPM... 99% of a street driven 'Vette is going to happen at less than 3000 RPM.
I realise your engine is probably biased more towards top end torque, but for people with daily driven Zs (like mine) it would be nice to see the whole story. I spend alot of time cruising at or below 1500 RPM and if I went to the trouble of building a stroker I wouldn't want to downshift much for passing!
Also, speaking of port widths, are you referring to LS1, LS6, or AFR intake port dimensions?
Thanks!
__________________
'02 EB/MR Z
Halltech Stngr, LGM Pro LTs, Stock Tune, 4 18" R2's on OEM Rears
11.86 @ 118, 1.82 60' (F1's), best 60' 1.80 (R2's)
80% Track, 20% Driver, 100% Z
How's the torque down low? One of my pet pieves is looking at dyno graphs that start at 3000 RPM... 99% of a street driven 'Vette is going to happen at less than 3000 RPM.
I realise your engine is probably biased more towards top end torque, but for people with daily driven Zs (like mine) it would be nice to see the whole story.
Thanks!
This would not be an engine of choice if your looking for a daily driver. This motor is a gorilla, and gorillas don't make good ballerina’s.
This would not be an engine of choice if your looking for a daily driver. This motor is a gorilla, and gorillas don't make good ballerina’s.
You underestimate the dual personality of this package. I could have easily added 10 more degrees of duration to this cam and put up an even larger "peak" number, but I specifically wanted to try and maintain a well balanced package....something a moderately aggressive enthusiast could drive every day. This motor is Dr. Jekyll and Mr. Hyde.....if its a gorilla its certainly one that cleans up real well when your driving her around town.
Lets put this in terms easier to understand. This engine is essentially an 11.0 to1 (total pump gas) 383 with a cam equivalent to a 234/238 hydraulic (it had the exact same engine vacuum with the current solid as it did with the 234/238 hyd. during my testing on the engine dyno). Certainly that is a middle of the road sized cam for a performance oriented vehicle of that displacement (bigger engines tolerate and need larger camshafts). If you were really building a conservative "daily driver" and fuel economy as well as passing the sniffer was a concern you would certainly want to go a little smaller, but trust me when I tell you that the car drives perfect from stoplight to stoplight and due to the extra displacement has MORE TQ available at low RPM.
Check out page 3 in this thread I started after engine dyno testing my current 383 and look for the comparison gragh between my original street oriented 346 with a 224/228 cam (a very powerful combination at 475/435 to the tire) and the package in my car right now.
While the graghs dont go as low as 2500 you can easily see that the 383 has more oats on the bottom and alot more oats at high RPM.
I will take an in car video of this package when I get her completely dialed in....and for any of you interested in the LA area, feel free to drop by AFR and we can go for a spin. Nothing like a 3rd party endorsement of the overall experience.
Tony M.
PS....The only area this combo gives up to my former very powerful 346 combination (when trying to compare the two for daily driving duties) is purely in the "stealth factor" at an idle the former package had with the more conservative cam. The 383 certainly has more lope....a nice steady chop at 900 RPM's that gives away a bit more of its performance intent, but cruising down the road she purrs like a kitten at any RPM in any gear.
I don't mean to drag this on... a few more details.
Your car in the vid - does it have the Z06 Ti system with cutouts on? If so, what's with the tips??? Also, are the cutouts open for that run?
At these power levels do you feel the 1.75" LG Pros are holding the engine back at all? Judging by the high RPM performance of your combo I'd guess that's a "NO".
Thanks again for some great work!
__________________
'02 EB/MR Z
Halltech Stngr, LGM Pro LTs, Stock Tune, 4 18" R2's on OEM Rears
11.86 @ 118, 1.82 60' (F1's), best 60' 1.80 (R2's)
80% Track, 20% Driver, 100% Z
I don't mean to drag this on... a few more details.
Your car in the vid - does it have the Z06 Ti system with cutouts on? If so, what's with the tips??? Also, are the cutouts open for that run?
At these power levels do you feel the 1.75" LG Pros are holding the engine back at all? Judging by the high RPM performance of your combo I'd guess that's a "NO".
Thanks again for some great work!
Thanks and have no problem about you asking for more details....details are good.
I built a custom exhaust for my car starting with the LG looooong tubes and high flow cats....dumps into the lightweight Z06 Ti mufflers that just prior to the entrance is a Y" pipe I fabricated which enables me to either route the exhaust completely thru the muffler or allow it to partially or completely bypass the muffler and head directly out the custom oval tips you see in the video (some of the exhaust will still go thru the muffler to balance the pressure but most of it will go to the point of least restriction which is the exiting tips). The chores of directing the gases are handled by a pair of QTP electric cut-outs which have worked flawlessly for me and are reasonably compact....more so than other alternatives. I have some pics if any of you guys would be willing to host them....One pic makes what I just tried to describe alot easier to understand. I did have my "muffler bypass" valve opened both idling and obviously blasting off down the road but keep in mind the exhaust does run the entire length of the car including passing thru both cats much earlier in the pipeline. When I open the cut-outs the exhaust is not dumping under the car etc. I will take some additional video footage at some point in the furure with the car idling and closing and opening the valve....its pretty cool and with the cut-outs closed the car still sounds healthy but with alot of the "edge" taken off.
Headers....I think the LG system is about the perfect system for a C5 street car that wants to place the emphasis on "street"....at least one that is stock displacement and a little larger. While Im sure a 1.875 header would have made 7-10 more peak, throttle response, and TQ below 4500 RPM's would have certainly been compromised. Its actually unbelievable that small (and long) a primary tube can get the job done at that power level (over 600 at the flywheel) but I do feel some of that is due to an extremely efficient cylinder head with strong low and midlift exhaust flow (helping to crutch what would have been too small a header in most similar situations). Its all about the combination and the results of this one were a little better than I had hoped for going to the dyno with high, but realistic goals.
Well, its about bedtime for me....catch you guys next time
Tony,
In some of your data you suggest the long tubes of the LG’s and the merge collectors could be holding you back at high RPM’s. While you have truly pointed your combination toward a dual purpose application it is slightly skewed toward the drag race side, (4.10 gears, etc). Do you think a 1.875” conventional header would hurt you that much even losing a small amount of torque on the bottom end with gains in HP on the top end in a drag race application? My other question is did you flow your heads using the LG's bolted on and did you try a different header, (larger tube) as well?
Thanks, D.J.
Last edited by OneQuickCoupe; 02-12-2006 at 03:22 AM.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
Another LS engine comin' up. 
Linear Mode
