Well its been almost three years since I featured the engine dyno results (and the extensive cam, heads, and parts swapping) on the 383 I built to feature our cylinder heads back in August of 05'. Ultimately the engine produced 610 HP on the flywheel dyno at just over 11 to 1 CR designed to run day in and day out on 91 octane. Im sure the older members on the board remember the thread, but for the sake of some of the newer guys, here is a link to the original testing....

http://www1.ls1tech.com/forums/showt...450&highlight=


Since then this engine has been on a handful of chassis dyno's (SuperFlow, DynoJet, DynaPack, etc.) occasionally testing and tweaking parts and trying small changes in general. For the most part the power has consistantly been in the mid 530's (RWHP) and 485-490 RWTQ.

Seeing as its been quite some time since its been strapped to a chassis dyno (and knowing that I will soon be pulling the engine to make room for a larger CID combo I am working on), I decided to see if she was close to her former numbers after all the time passed, carbon and crud build-up on the valves, the countless 7200 RPM shifts, and lets nots forget the few hundred times I have banged it off the 7400 rev limiter due primarily to excessive and explosive wheel spin on the street in the lower two gears (dare I mention the 8508 RPM 3-2 shift....yes I was logging data at the time!). My other big push towards the dyno testing was a track outting that was scheduled for tomorrow (private track rental....about 100 peope) and I wanted to make sure the engine was still producing at least close to what it used to....didn't want any surprises at the track questioning so-so results.

So with an early morning start and the help once again of Mike Haddad who loaned me his dyno and facilities, and the invaluable help of George Lara weilding the laptop, we were all pleasantly surprised with the outcome of todays test and tune. The first pull was right at 530....I was already smiling coming in pretty darn close to what it formerly run numerous times on the same dyno. However, George and I looked over the power curve and A/F ratio and felt there might be some opportunity with some fuel (and ultimately timing) changes. When the smoke literally cleared the dyno cell a few hours later we were left with the following results after slowly nickel and diming our way to more power....and by more power note that this represents about 8 more ft/lbs of TQ than my previous best (on the same dyno), and 5 more HP. The flat TQ curve and the way it carries peak power is a beautiful thing....





In fact, the last run of the day (the "hail Mary" run!) was a slightly cooler run after sitting a bit and it actually made 547/500, but Im posting one of the last few runs prior to that which it duplicated on numerous occasions today(give or take a single HP or ft/lb of TQ).

The only downer of the day was getting the phone call on my way home that the track outting on Sunday was cancelled and will be postponed two weeks....the weather called for no wind and a high of 55 with a slight overcast....the D/A would have been killer!

Looks like the 83' gets to stay together another couple of weeks....It really has been a fantastic combination. Just thought I would share

Regards,
Tony

 

Your making the 408 crew jealous now Tony

Awesome numbers and talk about consistant...

Once your done with that junk 383 you can just slide it over here, I'll pick it up to make it easier for ya....
JK

 

Good show, I cant wait to see your next combo!!!

 

In all seriousness Tony, what are you planning on doing with the motor ??

 

Thats pretty awesome the way it holds peak for so long. You dont usually see that. Then again, you dont usually see a 540/500 383 either.

 

what did this setup trap in the 1/4?

 

Like always awesome write up Tony and freakin awesome numbers.

Thanks for sharing.

 

Awesome numbers Tony. I was very happy to meet you in person at the Sema show this year and I was very impressed with your knowledge. I've always followed your posts on the techboard and it was great to put a face to a name. My buddy that was with me was so impressed that you made him decide to stick with Gen III heads yet! I myself am way too far along in the LS7 realm to look back now!! Also, thanks for some of the advice you gave us!Traver

 

those are some sick 383 numbers

 

Thanks Traver....

It was good meeting with you guys as well....good luck with your LS7 build and if your buddy needs any tips with his cathedral style build have him give me a shout. And thanks for all the other positive comments in this thread as well.

I have called this combo "the little engine that could" and it has really lived up to its name. I think the moderate displacement and optimized airflow from CAI to my exhaust tips and everything in between helps this small stroker really shine and also hang on to its power curve a bit longer than a larger displacment combo might. The TQ output from it is the most surprising and once again Im sure is related to the entire package working well togther. Some packages make less than the sum of their parts for no apparent reason and others make more. All the parts swapping and testing I did early on certainly helped Im sure....

Frost brings a question to the table I would have asked myself....and I like the fact he didn't ask what ET because ET gets too involved in other aspects of the run not related to power (tires, available traction, launch technique, overall set-up of the car, driver ability, etc.). Trapspeed is the direct indicator of power, and more precisely power to weight. If my car was 300 lbs lighter it would obviously trap a lot higher. The best thing about trapspeed is regardless of a good launch or a bad launch, the trapspeed is far more consistant. You can have a half a second difference in your ET based on traction and the other factors I mentioned above but your MPH thru the lights will typically be within a single MPH and usualy closer than that depending on conditions, DA, etc.

That said unfortunately I havent had a real good opportunity to see what this combo was/is capable of....today btw would have been the perfect opportunity. Its in the low 50's with zero winds....at a track some 650 feet above sea level I think we would have seen close to sea level conditions and quite possibly in the negative numbers....rare for us who race in the So. Cal area.

Due to my busy schedule I have only been to the track twice with this set-up in the last two years....one at the humbler of all race tracks that was recently closed (LACR) which has an elevation of 2700 feet and typical D/A's in the 4000 range. This was the track I went to first a few years ago when the 83' combo was new. It was suppose to be a shakedown pass with a new clutch at the time as well....leaving conservatively at 4K the track was prepped far better than I had realized and the car bogged so hard I thought the engine may have stalled. After getting back into the throttle and picking the nose back up in first gear I decided to run it out the back door just to see what it would do. To my surprise it ran an 11.20 @ 125 MPH and shortly thereafter I was asked to leave the track and come back with the proper safety equipment (no cage etc.). Note that was a very un-optimized run at a DA of 4100 feet....my car's raceweight btw is about 3400-3425 depending on how much gas I have.

The second and last time I was at the track was last summer at Famosa Raceway (where I was suppose to be today)...a far better track to run a number with a much lower elevation. The results of that evening was described here....

http://www1.ls1tech.com/forums/showt...446&highlight=

For those to lazy to look I had problems with my linelock and couldn't do a burnout....no traction equals another compromised run but with a much more indicative MPH this time....11.04 @ 129 MPH. Note the DA was alot better than LACR (around 1400-1500 feet that night) but nothing to write home about. Guess what....I was asked to leave that track as well after my "fabulous" lone run.

Sooooo.....here's hoping the weather conditions are better (in two weeks) and the track officials are more leniant!!....from what I hear thats the way it is at the private track rentals....we shall see. I have been working on installing a cage in my car btw and with a little luck it may even be finished by then.

Hoping to see 10 anything on the time slip (with a conservative 60 foot) and trap speeds in excess of 130 MPH....thats been my real goal all along with this combo. Based on the numbers and my raceweight I felt the car could trap over 130 MPH and thats getting with it (normally aspirated) in a moderate displacement stroker thats extremely drivable and user friendly on 91 octane pump gas.



Cheers,
Tony

 

Very nice work Tony, those are the traps to back up what the dyno says and to shutup the naysayers Best of luck at the rentals; post results.

Stop making this look so easy

 

Im curious as what valve springs were used.

 

hmmm , wanna sell the heads? The heads for my 383 are toast

 

So what are going to do with the 383?

 

Awesome. I'm thinking about adding a 383 to my AFR 205's. Need a FAST 90 first & a tranny rebuild.

 

Good question....

The shortblock I will freshen and resurrect into a slightly more milder combination with a hydraulic cam and a set of our 205's....basically Im building a new engine for someone using that short as the foundation. The entire top half I believe I have sold already (just waiting on a good faith deposit) but if things change there it will be availbale for purchase. I think that deal is solid also however....

Regarding the springs, they are a proprietary AFR spring... 1.550 diameter, double without a dampner, that we also sent out for cryo to enhance their life and keep the spring pressure around longer as well. You can also run 917 Comps....I have had good luck with those as well after the cryo process. Oh yeah about 210 on the seat and 550 open pressures.

Regards,
Tony

PS....In a few months I will likely post dyno results of the rebuilt 383 with the hyd. roller and a set of AFR 205's....it will be in a six speed Vette and tested on the same dyno so the numbers are actually worthy of comparison. There will be some exhaust and driveline variance of course but it wont be off by a country mile, thats for sure. It should make for an interesting comparo to the current slightly more aggressive solid roller/225 set-up. Im hoping for high 400's TQ and low 500's in the HP department.

 

Tony,

It is always a pleasure seeing you. I am seriously considering stroking my LS1 to a 383 with a set of your 205s. Those numbers are very nice. This little engine has proven to you, she is worth keeping. It will make a great engine for the person lucky enough to receive it, and I will do my best to make great numbers on it as well.

Get your roll bar finalized, and I will get plenty of videos of the little engine proving itself on the track in a few weeks.

On a side note folks, Tony's '83 matched the numbers from a stout max effort 403 we recently did. We did a comparsion and both graphs were nicely overlayed througout the entire range. Very impressive!

 

awesome info again Tony thanks for the hard work! im really impressed with these 205's and how well they perform even with the mild cam. the solid roller numbers are just ridiculous...i cant imagine what my car would be like making power all the way past 7000rpm (but i hope to at least spin to 7K when i get my 205's on my LS2) Keep up the good work sir!

 

Tony...how many actual miles do you have on your short block? That thing has probably been through more crap from you driving the **** out of it

 

Im either real easy on it cruising around town or killing it testing some new idea (or part) on my favorite stretch of road a few miles from my house (and AFR's new facility). It has been stellar in the reliability department with the only real maintenance issue being a broken valvespring a few months ago. I simply replaced them all just to be sure. It doesnt have quite as many dyno runs as my former 346 (literally logged over 400 with that engine) but its not far off that figure and I have logged waaaay more seat time with the stroker. I probably only have about 5000 actual miles on it but trust me it has seen the north side of 7K thousands of times....literally. Thats why the dyno results I got this weekend just roll me....this engine flat out likes the beating.....

ExTurbo, just to claify....my 83' has the 225 heads on it (not the 205's), but honestly there was very little difference when I compared the two on the engine dyno a few years ago. Check that thread if you would like more info...I would add however that the two heads were not swapped with the solid roller and the higher RPM's that cam helped provide. Good chance the 225's might have looked a little better had I compared the two in the final configuration of the engine. The larger cross section and additional airflow may have really shined above 6500 where most of the other testing was terminated with the hyd. roller sticks.

Regards,
Tony