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View Full Version : Can my motor handle a procharger?


MaxHarvard
06-30-2006, 04:27 PM
I'm seriously looking at getting one, once i find a real job in the real world! I'm just wondering what you guys think if i were to put it on the current motor... or would i need to beef it up, rebuild it and start over?

Currently, its a SBC 350 making 445hp and 445tq
4 bolt mains
stock crank shaft
forged rods
forged pistons
AFR 195cc heads, 2.02, 1.60
Xtreme energy 284 cam
6 qt oil pan
air gap intake
demon 750 carb
HEI distributor.

I'd really like to hit 550-600hp. Is my combo going to hold up, or do i need to replace some stuff?

Blown353
06-30-2006, 07:35 PM
What's the compression ratio and exact cam specs?

You'll probably be OK for a low-boost setup if your CR is around 9.0-9.5:1, although I would highly recommend a teardown to coat the pistons and open up the ring gaps a bit, which means while you're there you could benefit from a SC-specific grind cam.

What headgaskets are you currently running?

Carb mods and a boost retard of some sort (MSD 6BTM or equivalent would be easy) would also be a must.

550-600hp is not asking much if your CR is in the right ballpark.

Still, don't expect to do this for less than $4K or so, it adds up quick (SC & bracketry, good carb hat, carb mods, fuel system upgrades, etc, and I highly recommend spending the extra $200 or so to retrofit a GM spring tensioner on the SC bracket. Procharger's stock tensioner, in a word, sucks.

ProdigyCustoms
06-30-2006, 08:07 PM
Well, as Blown mentioned, compression and camshaft arer the two major factors. And he is correct, the 550HP to 600HP is a cake walk. I disagree on his cost estimate, $3000 should cover it. If the motor is 9 to 1 or so, and has the peoper camshaft, it will only need about 8lbs boost to make the goal. It will not take any rocket science to do a low boost carb mod, a special hat will not be required for just 600HP. There is plenty of $$$$ for fuel system upgrades left after the super charger pruchase (if you buy it at the right place hint, hint) and still do it for less then $3000 total.

Blown353
07-01-2006, 01:39 AM
Frank is right (as usual) but I'd still spend the money on a good hat even at low boost because the poor airflow distribution characteristics of junky hats will lead to some cylinders being leaner than others and may cause detonation issues. This isn't as big of a problem at lower boost / volume compared to high boost / volume but I strongly believe buying a good hat is money *WELL* spent. All sorts of driveability and performance issues can plague the engine with a poor hat and a good one isn't much more money.

There are a lot of bad hats out there and only a few good ones. I like SDCE's hat, CSU's hat, and the EV hat. I know Scott @ SDCE put a LOT of time into doing flowtests on all the hats out there, and I know he spent months doing the R&D on his hat to make sure it would deliver a very uniform amount of air to each barrel in the carb with all sorts of flowrates and boost levels with the hat pointed in any direction.

MaxHarvard
07-11-2006, 12:25 PM
Thanks guys... A lot for me to think about. I have 11:1 compression right now. I know i'd have to turn it down a bit.

Do you think those AFR heads are big enough? Also, will the stock crank hold that kind of power? I know the rods and pistons will.

The head gaskets i think are fel-pro... nothing too fancy i think.

EDIT:

How about selling this motor i have... and buying a Nelson Racing Engine blown 355? How would that be for you guys?

You think i could get $4-5K for my current motor with only 800 miles on it?

nitrorocket
07-11-2006, 01:23 PM
Lower the compression to 8:1 and you will be fine for 600+ RWHP with a Intercooled D1SC on 91 octane. The crank is by far the week link, it will be on the edge for sure.

Good luck! :D

Blown353
07-11-2006, 02:10 PM
Lower the compression to 8:1 and you will be fine for 600+ RWHP with a Intercooled D1SC on 91 octane. The crank is by far the week link, it will be on the edge for sure.

Good luck! :D

8:1 is too low and outside the efficiency range for a centrifugal IMO. I'm running about 9.2:1 on 91 octane, non-intercooled for now (water injection though) with 15 psi of boost through an intake that flows 305 per port and heads that flow 290/220 @ .600 (and have very good midlift flow and a very good I/E ratio across the board)-- so that 15psi of boost doesn't mean I'm trying to shove too much air through crappy heads/intake.

Given that supercharger cams are longer duration and "nastier" than turbo cams, having the compression ratio too low means poor overall efficiency when off-boost. That's OK for a race car but a bad move for a street car IMO. Better to keep the compression up some and the boost down a little to maintain off-boost mannerisms. Granted, you will sacrifice some of the all-out HP and boost potential that you could have with a lower static CR and more boost but the engine will be much more pleasant when off-boost with the higher CR.

Like anything, it's a series of compromises, and for a street car with a centrifugal going more compression and less boost is the way to go.

nitrorocket
07-11-2006, 04:23 PM
His cam really is not that big? :thumbsup:

Blown353
07-11-2006, 05:15 PM
His cam really is not that big? :thumbsup:

True, his current cam isn't big (he would benefit from a SC-specific grind with much more exhaust duration) but the combo will still be much more efficient off-boost with higher compression-- and you can still run plenty of boost with compression in the low 9's.

Majik16106
07-19-2006, 05:51 PM
have to agree here with blown. i tell people the same things when building motors for turbo import street cars. we bump supras all day to 9 or 9.5:1 to up the response time, run less boost and keep her 91 oct friendly.

Keeping the compression higher and boost lower results in some sick throttle response across the rpm band, which is great for passing while cruising without sounding like your going wide open to 8k rpm. from a roll races catapult the car forward if gearing is right. plus once again, the off boost driving is much nicer.. much easier to drive a car around a parking lot, or in traffic like on a cruise night or something.

im building a similiar set up.. 9:1 d1sc intercooled 355. I did opt for the forged crank and rods to go with the pistons, as this car is a street car, but when it hits a track , it would live at road atlanta, so thats a ton of high rpm corners and straights. makes for much better out of turn torque on twisty roads.

nitrorocket
07-20-2006, 08:59 AM
My car is plenty responsive with 8:1???? A 6 cylinder might nedd the added compression, but not a stout V-8. :D

3kidsnotime
09-11-2006, 04:32 PM
The least expensive part of a supercharged engine is the shortblock! All the money is what you put on top of it, If your engine runs good, Id leave it in the car and enjoy it while it still drives, You will be happy in the long run, Id build another short block and have everything ready, then do the switch and you have a good selling engine or short block if you use your heads, Go with a quality piston I would not use a heavy speed pro or trw they are quite weak the oil ring groove is slotted from side to side for the oil return, and they really dont like alot of cyl psi, For economy if thats where your at SRP has quite a good selection of off shelf piston as well as Probe keep static around 9.0 to 9.25 with aluminum heads on a centrifugal type supercharger, Youll need to figure your compression height to figure it out, Also a good thing to do is on the bottom of the cyl bore take a cartridge roll and run a slight radius on it This will help the oil from not being scraped off the piston, and fresh machine work from not cutting the skirts, Also go with a gapless second ring, Standard low friction rings rotate in the cylinder and if the gaps get about .250 alighn You will get a cutting torch effect and thats not good, Good luck on the project Jeff

camcojb
09-11-2006, 05:11 PM
The least expensive part of a supercharged engine is the shortblock! All the money is what you put on top of it, If your engine runs good, Id leave it in the car and enjoy it while it still drives, You will be happy in the long run, Id build another short block and have everything ready, then do the switch and you have a good selling engine or short block if you use your heads, Go with a quality piston I would not use a heavy speed pro or trw they are quite weak the oil ring groove is slotted from side to side for the oil return, and they really dont like alot of cyl psi, For economy if thats where your at SRP has quite a good selection of off shelf piston as well as Probe keep static around 9.0 to 9.25 with aluminum heads on a centrifugal type supercharger, Youll need to figure your compression height to figure it out, Also a good thing to do is on the bottom of the cyl bore take a cartridge roll and run a slight radius on it This will help the oil from not being scraped off the piston, and fresh machine work from not cutting the skirts, Also go with a gapless second ring, Standard low friction rings rotate in the cylinder and if the gaps get about .250 alighn You will get a cutting torch effect and thats not good, Good luck on the project Jeff

I would not use a gapless second ring. Worst thing I've ever done is to try them, they use oil, smoke, etc. I have not tried the gapless top rings and have heard they're better, but do a search on Total Seal gapless rings on most car sites and you'll get a ton of negative reviews.

Jody

3kidsnotime
09-11-2006, 05:25 PM
I have pulled a few engines down that they were installed upside down, And had major problems, I owned performance marine for 10 years and built an average of 200-250 supercharged engines a year and the last 7-8 years they are all we would use. I have seen a far cry more problems with a low friction ring. Im also wondering How a gapless second ring is affecting the job of the oil ring No oil should ever pass on the second ring, If the oil ring was doing its job??????

camcojb
09-11-2006, 06:40 PM
I have pulled a few engines down that they were installed upside down, And had major problems, I owned performance marine for 10 years and built an average of 200-250 supercharged engines a year and the last 7-8 years they are all we would use. I have seen a far cry more problems with a low friction ring. Im also wondering How a gapless second ring is affecting the job of the oil ring No oil should ever pass on the second ring, If the oil ring was doing its job??????

Like I said, do a search. Try Chevelles.com, Camaros.net., LS1Tech, etc. It is well documented. Could be for the same reason that they now put a bigger gap on the second ring than the top ring for improved sealing; maybe sealing the second ring is an issue, it's opposite of what the new ring gaps do.

I do not know why, but I know of several engine builders who used to use them, and do not anymore. I tried 4 times with pro shops doing the finish, etc. as per Total Seals specs, and they all smoked and all used oil. I went to the simple Speed Pro plasma file fits and ended all issues.

Jody

camcojb
09-11-2006, 06:43 PM
here's one from a quick search:


Here is something I have posted before so it's easier to just copy ithttp://www.chevelles.com/forums/images/smilies/smile.gif

I do not use or recommend gapless rings at all any more.
As for the Total Seal ones, every engine I have ever taken apart that had them had at least one & usually more of the gaps lined up.
Almost every performance engine builder I know advises against them.
I advise against them.
I have seen absolutely no gains except for the static leakdown numbers which don't tell you crap about what's going on under a load at RPM.
I have personally seen more crankcase pressure (blowby) at higher RPM's in the same basic engines with the 2nd gapless rings.
When you read magazine articles citing great gains with the newest widget try to remember who is paying for the article or the advertising in the magazine.
I use 004-.0045 top & ..005-.0055 second gaps on most performance engines except for KB's which I use very rarely.
Even the OEM's are going to larger 2nd ring end gaps & most major ring manufacturers are recommending a wider gap also.
Just a few of my thoughts on crapless 2nd rings http://www.chevelles.com/forums/images/smilies/biggrin.gif

I have not used the top gapless rings so I can't comment except to say that at temperature you have almost no gap with standard rings.
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3kidsnotime
09-11-2006, 07:01 PM
O well im new here and to each thier own thats what makes this world great, And just learing I guess we all are, If I did it correctly I inclosed a pic of one of my engines just off the dyno and the one in the back ground is going on in a few days, They each have those rings TSI TR9190 they are 4.505 5 over and untill I have problems with them Ill keep using them, Thanks

camcojb
09-11-2006, 07:05 PM
O well im new here and to each thier own thats what makes this world great, And just learing I guess we all are, If I did it correctly I inclosed a pic of one of my engines just off the dyno and the one in the back ground is going on in a few days, They each have those rings TSI TR9190 they are 4.505 5 over and untill I have problems with them Ill keep using them, Thanks

I agree, if they work for you then keep using them. :thumbsup: I've tried 4 times without success, and read many engine builders saying the same, so when I see a post about those rings I "jump in"! :D

Jody

3kidsnotime
09-11-2006, 07:10 PM
here's a couple of pics:

http://www.camcojb.com/el.jpg

http://www.camcojb.com/el1.jpg

tracy
09-11-2006, 08:12 PM
8:1 is too low and outside the efficiency range for a centrifugal IMO. I'm running about 9.2:1 on 91 octane, non-intercooled for now (water injection though) with 15 psi of boost through an intake that flows 305 per port and heads that flow 290/220 @ .600 (and have very good midlift flow and a very good I/E ratio across the board)-- so that 15psi of boost doesn't mean I'm trying to shove too much air through crappy heads/intake.

.

Blown, I am interested in hearing about your experiences with the water injection. I just don't see too many people on here that talk about using this type of setup.

camcojb
09-11-2006, 08:31 PM
Blown, I am interested in hearing about your experiences with the water injection. I just don't see too many people on here that talk about using this type of setup.

I used it on my Procharged 540 and we use it on my buddies 691 rwhp 406; both used 91 octane pump gas and no intercoolers.

On my Lightning and GTO I used alcohol and water or straight alcohol injection for similar results. Not a bad way to go on a pump gas forced induction build. Was worth 50 rwhp minimum on the Lightning with the extra boost and timing it allowed.

Jody

3kidsnotime
09-11-2006, 08:53 PM
I think we have taken away from MaxHarvard's thread this was his post and had gone away on other subjects, As far as your engine is ready for any form of supercharger it is not, Not to say its a bad engine it is just not a engine set up for a supercharger, If I have posted anything to take away from your question or intent im sorry, and great luck with the engine project. Jeff

fatlife
09-11-2006, 09:18 PM
some people call methanol "water" and some people also just use plaine water. My experience is that methanol works wonders, but you have to refill hte resevoir every so often. But my friend was able to run 20PSI on a single turbo with pump gas on a buick V6 using the methanol injection(and a big intercooler). If you have a MAF it will wire right in, and won't come on until you see like 5 PSI of boost