New motor disappointment

D3VST8R96GT

Well-Known Member
Joined
Feb 19, 2009
Messages
4,028
Reaction score
110
Location
Marble Fall, AZ
COMPRESSION COMPRESSION COMPRESSION!!!

Lets say with stock heads your compression was 8:1static with corrected dished pistons. Then you add cams that change the IVC location, this effectively altered your dynamic compression, now your 8:1static is nearly impossible to achieve because of effective compression.

Since you opt for tfs heads, raise your static to 11:1static with the .020" squish distance. Pump her full of air!

I can narrow down the actual static compression for your particular build if you specify all the technical.
Make a thread offering this service!

Not many will use it but squish squishes my brain.
 

spank 141

New Member
Joined
May 30, 2014
Messages
83
Reaction score
0
Location
So Cal
Dont dwell on dyno numbers so much. Dynos are more for tuning than to see how much you power your car makes. There are a ton of articles out there on how dyno numbers can vary and not be true to how much power a car is actually making. Rear gears and torque convertors change dyno numbers by quit a bit. A quick story and the reason why I looked up this very subject I took a car to get dyno'd and found that I had valve float. (easy to tell by looking at the HP curve it will be very erratic). Got the proper valve springs installed and took the car back to exact same dyno and tuner. The car now made 50rwhp less than it did with vavle float. At first I was like WTF that is not possible the car had a way better seat of the pants feel. Took the car to the track and it ran .6tenths quicker in the quarter with the proper valve springs and the dyno telling me I lost 50rwhp. The point is track numbers will tell you the real story not the dyno.
 

hottwheels04

Well-Known Member
Joined
Jul 14, 2006
Messages
2,153
Reaction score
13
yes dynos only matter so much, but 400rwhp with 14psi with a built trickflow heads cam motor? come on thats like 100-150+rwhp off from what it should be all day ... thats a bigg amount of power to be off not 20-40rwhp like most dynos vary, but when your missing 100+ hp either something is majorly wrong with your setup / motor, or your tuner is munipulating the numbers to read really low to get you to spend extra $ so you chase that number and spend tons more when in reality it is making the 500+ hp number you expect. its hard to trust tuners, around my area esp.
 

96blak54

Moderator
Staff
Joined
Feb 21, 2011
Messages
9,981
Reaction score
2,816
Location
In the shop
Same tuner used and the tuner knows his tools,. ... tuner could have given him a positive answer IF it was his tools or atmospheric conditions, but he didnt. We should be able to narrow down the problem when he gets back here.
 

ttocs

Post Whore
Joined
Oct 9, 2009
Messages
32,394
Reaction score
5,561
Location
Evansville Indiana
I am no motor expert but isn't a 255lph fuel pump feeding 8 60lb injectors possibly a little light when it needs it at full throttle? Can you see the fuel pressure?
 
OP
OP
torch318

torch318

Active Member
Joined
Aug 15, 2014
Messages
332
Reaction score
0
So all the paperwork for the specs on the motor is in my car two hours away at the tuners and I cant remember what everything is. I did make some phone calls today though talked to Greg at MMR he thinks that with my specs and boost that the power output is about right for my build he did want a compression test done and the plug gap checked. That is not what I was expecting as I was expecting power to be around 480ish. Called my tuner to see what my IAT's were at before we did the overdrive crank pulley and he said that he didn't datalog the IAT's but the timing for the pull ranged from 18-14 degrees. When I asked him about the timing on the second pull he admitted that the 425 hp number was not the finall pull and it ended up at 350 hp and he never really did tell what they were. As for the fuel I'm running twin 255's on a return style system.
 

Wichers123

Well-Known Member
Joined
Apr 21, 2013
Messages
1,203
Reaction score
0
Location
Covington, louisiana
So all the paperwork for the specs on the motor is in my car two hours away at the tuners and I cant remember what everything is. I did make some phone calls today though talked to Greg at MMR he thinks that with my specs and boost that the power output is about right for my build he did want a compression test done and the plug gap checked. That is not what I was expecting as I was expecting power to be around 480ish. Called my tuner to see what my IAT's were at before we did the overdrive crank pulley and he said that he didn't datalog the IAT's but the timing for the pull ranged from 18-14 degrees. When I asked him about the timing on the second pull he admitted that the 425 hp number was not the finall pull and it ended up at 350 hp and he never really did tell what they were. As for the fuel I'm running twin 255's on a return style system.
Huh? So you ended up with even less power? Something is wrong. Also is it 18* or is it 14* I mean at wot the timing should be be what it is. To give you an idea on 93 pump 10%E I run 15* of timing and it's pretty close. I could back it down a bit.
 
OP
OP
torch318

torch318

Active Member
Joined
Aug 15, 2014
Messages
332
Reaction score
0
Huh? So you ended up with even less power? Something is wrong. Also is it 18* or is it 14* I mean at wot the timing should be be what it is. To give you an idea on 93 pump 10%E I run 15* of timing and it's pretty close. I could back it down a bit.
Im assuming it's 14* for wot and that was just the rangr for the pull
 
OP
OP
torch318

torch318

Active Member
Joined
Aug 15, 2014
Messages
332
Reaction score
0
What valve springs? What lash adjusters? And did you check the lash?
MMR said that the springs are matched to the cam when theey installed them. Finally talked to the shop that installed the motor after their phone lines weren't working yesterday and he said that they did not check the lash adjustments didn't think there was a reason to which was my thought as well if you have to start double checking their work where do you stop? Then you might as well of done the whole build instead of hiring a professional.
 

96blak54

Moderator
Staff
Joined
Feb 21, 2011
Messages
9,981
Reaction score
2,816
Location
In the shop
I totally agree!

I assisted in a supercharged 5.4l dohc build with a friend. After multiple dyno attempts to extract more power with consecutive bolt ons and such, the power level stayed the same. Puzzeled as to why and very frustrated he decided to pull it all apart. With the highest attention to detail, we discovered the lash adjusters were causing the problem. This is because the valve train is so tight tolerance, the lash adjusters were lifting the valves off the seats at high oil pressure rates (high rpm). Solution was lash the adjusters in. Simple material removal/adding of lasher bottoms was the fix. 600rwhp wasnt enough but now he touches 750rwhp at 4500rpm before the 8 rib belt slings off. Im in process of machining him out a 10rib 10" crank pulley now along with the acc pulleys too.
 

Wichers123

Well-Known Member
Joined
Apr 21, 2013
Messages
1,203
Reaction score
0
Location
Covington, louisiana
I totally agree!

I assisted in a supercharged 5.4l dohc build with a friend. After multiple dyno attempts to extract more power with consecutive bolt ons and such, the power level stayed the same. Puzzeled as to why and very frustrated he decided to pull it all apart. With the highest attention to detail, we discovered the lash adjusters were causing the problem. This is because the valve train is so tight tolerance, the lash adjusters were lifting the valves off the seats at high oil pressure rates (high rpm). Solution was lash the adjusters in. Simple material removal/adding of lasher bottoms was the fix. 600rwhp wasnt enough but now he touches 750rwhp at 4500rpm before the 8 rib belt slings off. Im in process of machining him out a 10rib 10" crank pulley now along with the acc pulleys too.
What? That makes no sense. Lash adjusters just push the rocker arm to the cam and the valve. Valve float is what your describing and that's because the springs can't hold the valve close.
 

96blak54

Moderator
Staff
Joined
Feb 21, 2011
Messages
9,981
Reaction score
2,816
Location
In the shop
I know what valve float is...Wichers! Im describing a hydraulic actuator completely extended underload operating a cantilever finger follower with a 1.8ratio... operating a valve.
I can break this down if you guys need it, but lets let the OP investigate other possible issues.
 
OP
OP
torch318

torch318

Active Member
Joined
Aug 15, 2014
Messages
332
Reaction score
0
I know what valve float is...Wichers! Im describing a hydraulic actuator completely extended underload operating a cantilever finger follower with a 1.8ratio... operating a valve.
I can break this down if you guys need it, but lets let the OP investigate other possible issues.
I didn't have a very good understanding of how a lash adjuster worked before but after doing some reading on it I was wondering if you could clarify on how you check lash adjustment on a uninstalled motor? Don't they need oil pressure on them to see if they are working properly or is the internal spring pressure all that's needed?
 

Kboss87

Member
Joined
Aug 19, 2013
Messages
205
Reaction score
0
Location
Southeastern, PA
As stated, the P1SC is being entirely over spun. Fix this issue first.

Either upgrade to a D1, which you should minimally have for your set-up anyway....or slow the P1 down. You're new engine is more efficient than your last, so if you run the same pulleys as your last set-up, your boost psi will drop but you will still make more power.
 
OP
OP
torch318

torch318

Active Member
Joined
Aug 15, 2014
Messages
332
Reaction score
0
That was my initial plan but my tuner recommended the eight rib kit over the d-1 because he thought the d-1 would make more heat than my two core could handle. I'm thinking a d-1 spun slow vs a p1 spun fast would make less heat at the same boost on a two core? I'm going to do some blower speed calculations when I get a chance and see what my 3.1 pulley will spin it to with the o.d. crank pulley or if I would be better off pulling the od pulley and hopefully get those IAT's down. It would really be helpful if I knew what the IAT's were from all three tunes.....
 

Latest posts

Forum statistics

Threads
77,440
Messages
1,502,175
Members
14,920
Latest member
marktuck99

Members online

Top