Stroker Performance Review
- Thread starter Ivoryk3ys78
- Start date
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Ivoryk3ys78
Well-Known Member
Well we discovered that the throttle wasn't opening all the way by a half an inch or so.. defnitely enough that it was squiring gas in that last bit. Thought we had that right but doing so many things. Not saying that is the problem but definitely a positve step.
B3422w5
Well-Known Member
if it were 390 per inch, at 1.9 wouldn't it be almost 770 ish...lol
Something in the equation is off
good find.... likely a few hundreds
j par
Well-hung Member
I wasn't really meaning to totally bust your seeds personally about the eagle cast crank.. because everybody was talking about it six years ago is the reason I bought the scat cast crank...
Because his first couple runs weren't as strong as he would have liked them really shouldn't be an indication to start buying carburetors torque converters shimming Springs and good Lord changing out the crank.. I can't remember my speed but I'm almost positive I was well into the mid 12's on my first few passes with my new Stroker motor... When it was new 6 years ago.. I whittled it down to an 11.5 pretty consistently but felt 118 - 119 mile an hour should have been yielding high tens... But with lack of funds for a few more good suspension parts and a lot more seat time and mind you this all with a 4-speed I wasn't able to get there but still wasn't never and still am not disappointed with my build...
My point being if he was to follow all these four to $500 or more suggestions it would probably ruin his high for the hobby and end up going all bad. It sounds like he's got a nice fun car with lots to learn... And emptiness pockets out day 1 that's not going to help.
Personally if I would have chose an eagle cash crank I would have ran it till it broke..
I don't think I have 200 total passes on my car now so I don't think I would have killed it yet...
Anyways I wasn't meaning to get on you personally..
j par
Well-hung Member
Also I think it was 318 that proclaimed it the slowest stroker on the internet and I just ran with it LOL... Besides being an internet supermodel it's my claim to fame....
Ivoryk3ys78
Well-Known Member
Well this is what's in the trickflow Instructions
"Valve Springs Standard: 1.460” O.D. Dual Spring (TFS-16893-16) 120 lbs. @ 1.900” Installed Height 394 lbs. @ 1.175” Open 390 lbs./inch Rate .650” Maximum Valve Lift
"Valve Springs Standard: 1.460” O.D. Dual Spring (TFS-16893-16) 120 lbs. @ 1.900” Installed Height 394 lbs. @ 1.175” Open 390 lbs./inch Rate .650” Maximum Valve Lift
- Installed Height/Pressure: 1.800"--145#
- Pressure @ .550" lift: 358#
- Pressure @ .600" lift: 375#
- Pressure @ .650" lift: 400#
- Pressure @ .700" lift : 425#
- Coil Bind: @ .750" lift
- Outer Spring ID/OD: 1.075" /1.459"
- Inner Spring ID/OD: 1.078" / .794"
- Type of Spring: Dua
Spring Rate 391
Phreakish
Well-Known Member
A spring rate of 390 and a load of 120 tells you the spring is shortened by 0.308 when installed. With a 1.9 height, that's a "free" length of 2.208 before installation.
Spring load is equal to original length minus final length times rate. Or R*(Li-Lf).
You can also add load plus the quantity change in length times rate. For example, if the load is already 120 and you add 0.100 more preload, you can do the following: 120 + (390*0.100), which would be 120+39, or 159 lbs.
Also, subtract the added preload from max lift. If max lift was 0.650 and 0.100 of preload is added, max lift is now 0.550.
Clear as mud?
Spring load is equal to original length minus final length times rate. Or R*(Li-Lf).
You can also add load plus the quantity change in length times rate. For example, if the load is already 120 and you add 0.100 more preload, you can do the following: 120 + (390*0.100), which would be 120+39, or 159 lbs.
Also, subtract the added preload from max lift. If max lift was 0.650 and 0.100 of preload is added, max lift is now 0.550.
Clear as mud?
Ivoryk3ys78
Well-Known Member
Yeah.. it makes my head hurt a bit.. It confirms though what made sense to me. Spring rate per inch X Shim thickness added to original spring load at original install height will give the new pressure assuming the springs test out to match what they are rated at.
It does got me thinking that maybe I couldn't run a .060 shim though. The cam is 600/615 lift at 1.5 and .018 lash. Seems like .060 could push it over just a bit. Though I am sure some is lost in inefficiencies with geometry but going by the numbers I guess it would be pushing it a bit.
It does got me thinking that maybe I couldn't run a .060 shim though. The cam is 600/615 lift at 1.5 and .018 lash. Seems like .060 could push it over just a bit. Though I am sure some is lost in inefficiencies with geometry but going by the numbers I guess it would be pushing it a bit.
Ivoryk3ys78
Well-Known Member
Yeah I don't understand this. Trickflow shows its 120@ 1.9 and at that spring rate if it was shimmed to 1.8 it would become like 160.
You guys make me thank God I have a spring pressure tool. My head hurts.
PRH
Well-Known Member
The PAC specs for the 1903 from their catalog are:
120@1.875/394@1.175, 391lbs/in.
In their load chart, they show 110@1.900, 130@1.850, 149@1.800.
I have installed tons of these springs.
My obsevered spring loads agree with the catalog....... basically 150@1.800, which is where I usually set them up for fast rate SFT cams.
I have a set of new TFS-16893’s that came off some PP240 heads.
I just checked one....... 112@1.900
The specs that come in the paperwork supplied with the TF heads don’t agree with the specs on the TF site in the valve spring section(where the specs for the 16893 are exactly the same as what PAC shows for the 1903).
120@1.875/394@1.175, 391lbs/in.
In their load chart, they show 110@1.900, 130@1.850, 149@1.800.
I have installed tons of these springs.
My obsevered spring loads agree with the catalog....... basically 150@1.800, which is where I usually set them up for fast rate SFT cams.
I have a set of new TFS-16893’s that came off some PP240 heads.
I just checked one....... 112@1.900
The specs that come in the paperwork supplied with the TF heads don’t agree with the specs on the TF site in the valve spring section(where the specs for the 16893 are exactly the same as what PAC shows for the 1903).
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PRH
Well-Known Member
The catalogs aren’t always correct.
There’s what your paperwork says the springs are........and then there’s what they really are.
Sometimes those agree with each other...... but fairly often they don’t.
In the case of the PAC 1903, my measurements are very close to the advertised specs from the PAC catalog.
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Lol. That's why I put a digital readout on my spring tester.
Plus I can see how much shim to use for desired seat pressure. No calculator.
Phreakish
Well-Known Member
I deal with a lot of springs. The thing I know for sure is that the rate is very highly dependent on the wire diameter and the total length of wire in the spring. A variance of .001 changes things to a significant degree. This is why PAC springs are awesome - they control everything down to the gnats ***.
That said, the discrepancy between the catalog numbers and the numbers in reality probably comes from manufacturing tolerances. Almost every material made will come at the very min diameter, min thickness, min everything because material manufacturers are cheap bastards. The engineering is all done to 'nominal' sizes though. If a .100 shim only adds 30 lbs, and not 39 then the rate is closer to 300 than it is to 391 - or the installed load is lower than advertised. This can happen for a lot of reasons too. Rate is often measured on a 'new' spring, but once a spring is compressed beyond the intended working height, it will take a 'set' and everything changes (rate, pitch, preload, etc). There's also spring 'creep' which happens to almost any spring left in any amount of compression for long periods of time.
All this to say: never go strictly by the numbers, they're only there for doing the initial work but MUST be verified by measurements otherwise you simply cannot know. Just like compression ratio, installed centerline, etc.
That said, the discrepancy between the catalog numbers and the numbers in reality probably comes from manufacturing tolerances. Almost every material made will come at the very min diameter, min thickness, min everything because material manufacturers are cheap bastards. The engineering is all done to 'nominal' sizes though. If a .100 shim only adds 30 lbs, and not 39 then the rate is closer to 300 than it is to 391 - or the installed load is lower than advertised. This can happen for a lot of reasons too. Rate is often measured on a 'new' spring, but once a spring is compressed beyond the intended working height, it will take a 'set' and everything changes (rate, pitch, preload, etc). There's also spring 'creep' which happens to almost any spring left in any amount of compression for long periods of time.
All this to say: never go strictly by the numbers, they're only there for doing the initial work but MUST be verified by measurements otherwise you simply cannot know. Just like compression ratio, installed centerline, etc.
yellow rose
Overnight Sensation
It’s not so much spending his money, but anyone should see his converter is wrong for his combination.
Way too many people are, for whatever reason still thinking about converters like the converter technology was in 1980.
I personally know guys running 8 inch case, 8 inch stator converters with 5k plus stall speeds in street driven cars. Without issue.
That was one thing that jumped out when reading the OP. You can make all the power you want, but if the converter is wrong, it will never perform like it can.
The carb is small. Is that killing it? Not like the converter is. There are a few other things that could be tuned up, but the converter is by far the biggest thing showing itself as being wrong for the OP’s car.
How many more trips to the track before the day on the dyno pays for itself. In money, time, frustration...everything.
Had the engine been on a dyno, it would have made converter selection much easier.
It’s all about the package. Time is money. I still kicking myself in the groin for not putting my junk on the dyno, so that is happening before it goes back in the car.
I hope I didn’t post this already in this post but my son picked up .60 going from a 4600 stall converter to a 5600 stall in a well sorted out car. And that was in a car the ended up deep into the 10’s.
Thanks... my Dart just got a boner.
yellow rose
Overnight Sensation
Ivoryk3ys78
Well-Known Member
Well I asked for feedback and what I do with it is my responsibility. So I certainly wouldn't want people to hold back what they think or temper it because they think it would overly encourage me to spend too much money.
The converter I had bought for a 318 last year that was hopped up some. Then I got to building this 408. I didn't realize that converters had changed so much but it has been in my mind that the converter may be on the smaller side. This is something I would like to upgrade as money allows.
My main concern to start with is the engine output. I will do leak down and compression testing and if all that looks right upgrade the fuel system with new Carter Strip pump and 3/8 line and pickup and fuel pressure regulator to eliminate that as a possible issue. Also shim the springs to get the seat pressure where it should be. From what I learned in this thread with Trickflows discrepancy that it is really more like 110 at the seat most likely and it should be more in the 135-145 area.
Then its a matter of going to the track and will have another carb on hand a Proform 850 and work with timing and carb and hopefulyl get much more then 2 passes this time.
Thanks
The converter I had bought for a 318 last year that was hopped up some. Then I got to building this 408. I didn't realize that converters had changed so much but it has been in my mind that the converter may be on the smaller side. This is something I would like to upgrade as money allows.
My main concern to start with is the engine output. I will do leak down and compression testing and if all that looks right upgrade the fuel system with new Carter Strip pump and 3/8 line and pickup and fuel pressure regulator to eliminate that as a possible issue. Also shim the springs to get the seat pressure where it should be. From what I learned in this thread with Trickflows discrepancy that it is really more like 110 at the seat most likely and it should be more in the 135-145 area.
Then its a matter of going to the track and will have another carb on hand a Proform 850 and work with timing and carb and hopefulyl get much more then 2 passes this time.
Thanks
j par
Well-hung Member
well I can't talk converters at all but I know they have a lot to do with performance. Also I know you're on a major Dino kick right now because you're going to actually take your own motor down to the Dino and maybe looking to convince other people to do the same.
so if you didn't take it down to the Dino and he did take it down to the track and spent that much money trying to get his combination straight wouldn't he also learn a lot more about driving his car? You know the whole package the whole combination?.. the reason he built the motor in the first place likely...
You said it before you don't like the track you detest the nose picking people that lean up against the fence and watch. now why would you want to spend any time they're trying to get your car to go faster when you don't even go to the track???
That's a 360 car, isn't it?
yellow rose
Overnight Sensation
You’re missing the point. The dyno shows the power curve, which makes getting the converter correct (or a good starting point for clutch tuning) much easier.
I’ve been about using the dyno for more than 20 years. I would have had the BEST dyno west of the Rockies in 2003 if the jackass criminal I worked for wasnt a jackass lying criminal.
From June of 2003 until January of I worked where there was a dyno right there.
Used correctly, a dyno saves time, money and frustration. Even on a street drive car. With the number of dyno’s around the PDX area, it’s crazy to not use one.
I can name 7-8 engine dyno’s and several chassis dyno’s within an hours drive of Portland. Make the 8 or 9, because I forgot about the dyno that AndyF uses on regular basis.
I would be concerned about the output too..
But you said your converter was built for a 318 ?!?! My money is on THAT being the problem, for the most part. Your new motor is driving through it.
I don't know what converter you have (who made it) but I would send it back and correct it for your new combo. Maybe $250, more if they change the stator. (probably)
If you have a stock 10 3/4 lying around, throw it in, shift it at 5800 and see how it MPH's... if it gains 4-5 mph, you've found your issue.
TrickFlows QC is probably a lot better than Edelbrock's QC... I had a OOTB E Streets in my shop a couple weeks ago, and the Valve seat run-out was horrendous!
Don't put too much stock in the Leak-Down testers.. They are finiky with piston possition and tend to show a false negative.
A compression check should suffice, as long as they're consistent, cyl to cyl.
PRH
Well-Known Member
The point that’s trying to be made about the converter is........ the OP is basing the engines power output by the cars performance data.
Many things affect the cars performance other than the power output of the engine.
The converter being probably the next biggest player.
If the converter sucks(and many do), the cars performance will be way off, making the power output appear to be low.
This is where having dyno tested the motor is probably the most valuable.
If the motor made 550hp.......... but the car is running 450hp ET’s........ you know where not to spend any money.
On the motor.
Of course, without the dyno....... the builder is “assuming” that magic combo of parts “should” make 550hp....... but without testing, who knows?
Maybe it’s actually only making 450hp(or 475, or 500, or 600??).
The question as to whether there is sufficient valve spring load to maintain valvetrain control to the RPM they’re turning the motor would have been answered as well.
Many things affect the cars performance other than the power output of the engine.
The converter being probably the next biggest player.
If the converter sucks(and many do), the cars performance will be way off, making the power output appear to be low.
This is where having dyno tested the motor is probably the most valuable.
If the motor made 550hp.......... but the car is running 450hp ET’s........ you know where not to spend any money.
On the motor.
Of course, without the dyno....... the builder is “assuming” that magic combo of parts “should” make 550hp....... but without testing, who knows?
Maybe it’s actually only making 450hp(or 475, or 500, or 600??).
The question as to whether there is sufficient valve spring load to maintain valvetrain control to the RPM they’re turning the motor would have been answered as well.
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