- Joined
- May 27, 2001
What is going on in this thread?
Constructive criticism is fine, but let's not get too harsh.
Constructive criticism is fine, but let's not get too harsh.
dyno numbers with GN-1's and roller cam DISSAPOINTMENT
- Thread starter slimtastic
- Start date
- Joined
- May 27, 2001
So if your RWHP is around 364 that means you are making around 430HP at the crank.
Obviously you will need more rpm to better match the cam.
On race gas I would expect over 540RWHP.
^Ed made 527RWHP running out of fuel with Iron Heads and a old school school PT64/66 Ptrim.
Obviously you will need more rpm to better match the cam.
On race gas I would expect over 540RWHP.
^Ed made 527RWHP running out of fuel with Iron Heads and a old school school PT64/66 Ptrim.
KL Mallender
Certified Dumb****
- Joined
- Apr 16, 2007
My last post for those that wish to learn,
A short duration/high rate of lift camshaft put's undue stress into the springs when opperated beyond their frequency.
Compounding the problem with 1.65 rockers will lower the rpm at which this frequency will be reached.
Now, if that isn't enough, add up the extra weight of the roller lifter itself to it's maximum rate(mid to full lobe lift) you quickly run out of enough spring pressure to control lifter "float', the valve get's the rough end of the deal/blame, but it is the weight of the lifter that starts the process, the instant this happens, a "Hydralic" lifter takes up the slack(preload) and keeps the valves off their seats for a few extra degrees, effectively de-compressing the engine at the critical rpm in question.
This is easily read/tracked when an EGT guage is used, the exhaust temperture soars when valve float occurs.
Some use this information incorecctly, they see high EGT's and start retarding the ignition.....wrong.
Fix the springs first, and you will be needing a whole lot more pressure than you might think correct, but it's the truth.
Getting enough spring/pressure vs installed/full lift heights is no easy task in a Buick, cutting spring seats is almost essential when using non-stock camshafts.
I'm not here to argue(suprise), it is of no consequence to me whether you listen or you don't, I only offer what I've learned to those that are willing to listen, and it is my experience with people that tells me to charge extra money to those that won't pay attention.-end-
Best of luck to you,
Kevin.
A short duration/high rate of lift camshaft put's undue stress into the springs when opperated beyond their frequency.
Compounding the problem with 1.65 rockers will lower the rpm at which this frequency will be reached.
Now, if that isn't enough, add up the extra weight of the roller lifter itself to it's maximum rate(mid to full lobe lift) you quickly run out of enough spring pressure to control lifter "float', the valve get's the rough end of the deal/blame, but it is the weight of the lifter that starts the process, the instant this happens, a "Hydralic" lifter takes up the slack(preload) and keeps the valves off their seats for a few extra degrees, effectively de-compressing the engine at the critical rpm in question.
This is easily read/tracked when an EGT guage is used, the exhaust temperture soars when valve float occurs.
Some use this information incorecctly, they see high EGT's and start retarding the ignition.....wrong.
Fix the springs first, and you will be needing a whole lot more pressure than you might think correct, but it's the truth.
Getting enough spring/pressure vs installed/full lift heights is no easy task in a Buick, cutting spring seats is almost essential when using non-stock camshafts.
I'm not here to argue(suprise), it is of no consequence to me whether you listen or you don't, I only offer what I've learned to those that are willing to listen, and it is my experience with people that tells me to charge extra money to those that won't pay attention.-end-
Best of luck to you,
Kevin.
Can't agree with that...I have a very similar cam, with ported iron heads, no work done to the spring seat and an off the shelf spring...Runs good to 6000, just need to talk to a good vendor and pick out the correct spring...And PS he has Aluminum heads which "should" make spring selection even easier.
Too the OP, seriously you need octane and boost...My car has a stock shortblock (mostly) and I spin it 6000, probably would quit there personally.
Just as an example, when I dynoed my car at 21 psi or so it made 450-470 somewhere in there (wasn't really paying attention was trying to get the fueling right so I could turn it up), then I rolled 5 pounds of boost into it and made about 570.
What kind of dyno is it?
Oh and I've never seen a Buick get a clean tach signal from a plug wire due to the wastespark system, if you're shop has an optical sensor slap a white piece of tape on the crank pulley and use that it works much better.
- Joined
- May 28, 2001
Slim your combo is a good one but you will run into a wall soon and it's called octane. I would highly recommend an alky kit from Razor for your set up. If you don't you will be hurting parts and head gaskets.
The theory about your valve springs is off. Those springs will work fine. I'm using them on two street motors and a Stage car that shifts at 6800 all day long. All three cars pull like freight trains right up to their shift points. They work very well.
If the BS3 can handle those injectors at such low duty cycles that is great but they are overkill for your combo. If you do go with an alky set up, you will be reducing that duty cycle even more to compensate for the alky. Food for thought.
It's a shame you could not get a torque reading you are probably making 500 lb-ft of torque already.
It's in the tuning but protect the motor with alky or a steady diet of race gas.
Good luck.
The theory about your valve springs is off. Those springs will work fine. I'm using them on two street motors and a Stage car that shifts at 6800 all day long. All three cars pull like freight trains right up to their shift points. They work very well.
If the BS3 can handle those injectors at such low duty cycles that is great but they are overkill for your combo. If you do go with an alky set up, you will be reducing that duty cycle even more to compensate for the alky. Food for thought.
It's a shame you could not get a torque reading you are probably making 500 lb-ft of torque already.
It's in the tuning but protect the motor with alky or a steady diet of race gas.
Good luck.
Pronto
Believe nothing you hear and half of what you see.
- Joined
- Dec 9, 2002
Sorry Dude, your a fool to spend money on those go fast parts just to run 15lbs on 93. An unopened stock block with a TA49 would make the same power and be more responsive. Either run the good stuff or add alky. Then turn that boost up to 27lbs and then see what happens. Why would you put a top end and cam capable of low tens and wants to live at 5800+ rpm on a stock bottom end?
DailyDrifter
The Slow and the Curious
- Joined
- Dec 5, 2007
If you aint living on the edge....your taking up too much space
turn up the boost and let it eat.The power is definitely off. It should be making about 80-90whp more. Your timing is not even close. You need about 8-10* more at that boost level. Id bet you will see about what youre missing. Thats the timing i run at 30psi with a 9:1 or higher CR engine. Id verify the timing indicators are accurate. Then be sure the ring is accurate and offset the variance and crank it up. 11:1 is a lot richer than it needs to be at that point too. You can probably lean it to 12:1 and pick up even more. With the wastegate arm disconnected i made 413whp@13psi at 5800rpm. Race ported GN1 heads and 218/224 cam. It was still climbing but was just checking to be sure everything was good before i threw any real boost at it. You should be able to get a lot more out of your combo with some simple checkpoints and more timing. Boost goes up timing goes down. Boost goes down timing goes up. If your timing table looks like a bunch of 21's from any point where the engine starts making boost and up you will have an engine that makes crap for power (unless you have it at 25+psi) and is a lazy turd on the street. The difference between 369whp and 450whp is huge. Forget about 93 octane if you want to make any power
slimtastic
yea dude...I rock
- Joined
- Aug 9, 2002
20 lbs at 20 degrees on pump 93
thankyou for the response. i really thought that with the mods the power would be off inthe 400's and climbing but as it sits the power will level off and actually start to drop a little near redline. ill go check a few items. also i couldnt add any more timing to the motor at 15 lbs or it would loose power, i was thinking 25 degrees at 15psi would live...
turbo nasty
Turbo Dojo / MNTR
- Joined
- Jul 19, 2001
As stated increase cylinder psi...that be more timing and/or boost. With the increased cylinder psi octane increase is needed as well. Combo and tune is where its at! Good luck let us know how it goes when you tweak it further
If youre trying to make as much power as possible on 93 octane you need to build an engine around that. Driving it will not be fun either. Your missing item is octane on this one. You made 6 less hp at 2 psi less boost. If you had the 2 psi boost back in there you would be well over the old engine. You havent really changed much to increase the airflow through the engine. The rpm and ci will detemine the cfm flow through the engine. Rpm is the only way you will get more mass flow without increasing boos. If you want power with low boost that will net more than anything else. The power band will move up and get narrower. Id suggest filling it with 116 octane and making some 25psi blasts with it. Once you do you will forget all about 93 octane.
He doesnt need a lot of spring pressure with that cam and cutting the seats isnt needed either and you cant cut them too much on a GN1 either. You can get 200-220lbs on the seat and over 500 open with springs that will fit with the stock valves on a set of GN1 heads. More than just about any hyd roller application would need to run 6000 rpm and 30psi boost. If you need more pressure for a solid roller you can get a set of Chevy valves that are about .100 taller and the selection of double springs available will have just about anything covered.
IMHO, you need to clearly define what the goal is...... max power on pump gas?
Really.... 15 psi isn't going to make much power relative to what you could be making with pump gas and alky, or race gas.
With the good GN1 heads.... that cam is screaming to be turned 6500+ RPM. For $500 or so for an alky kit.... I'd be running that combo at 24 psi or so with pump gas and alky and shifting at 6300 - 6500..... timing around 20 - 21 deg @ 24 psi boost if it liked it.
I think you would be much happier there.
Really.... 15 psi isn't going to make much power relative to what you could be making with pump gas and alky, or race gas.
With the good GN1 heads.... that cam is screaming to be turned 6500+ RPM. For $500 or so for an alky kit.... I'd be running that combo at 24 psi or so with pump gas and alky and shifting at 6300 - 6500..... timing around 20 - 21 deg @ 24 psi boost if it liked it.
I think you would be much happier there.
that cam isn't going to make good power past 6000rpm with less than 30psi boost. It will likely peak around 5300-5400@25psi boost.
slimtastic
yea dude...I rock
- Joined
- Aug 9, 2002
my goal would be 450-460 on straight 93 and then 500 plus on 93/alky with full power right at redline (as most people around here love to roll race so id like to hang a little).....
however since the car didnt get any gains from the low boost "rough in tune" im inclined to believe that somthing is mechanicly wrong due to the fact that from the inital 10 lb strart to the 15 lbs finish for this quick dyno session i basicly have 12 hp per pound of boost from 304 at 10 to 364 at 15.
i find it difficult to believe that from 15 lbs to 20 i could gain another 100 hp (basicly gaining obsurd ammounts of power for each pound from this point) kinda feel thats what everyone seems to be hinting at.
ill turn the redline up to 6000 tho....
