Help with disappointing dyno results
07-06-2018, 09:31 PM
#41
Instructor
Thread Starter
That seems to be the consensus. I’ll have to go with a mini ram since the super ram is impossible to find anymore. I probably should have gone with AFR 195,s as well but I’m not sure I can justify tossing the 180 elims. Can these heads be ported to give me what I need?
07-06-2018, 09:50 PM
#42
Melting Slicks
That seems to be the consensus. I’ll have to go with a mini ram since the super ram is impossible to find anymore. I probably should have gone with AFR 195,s as well but I’m not sure I can justify tossing the 180 elims. Can these heads be ported to give me what I need?
07-07-2018, 06:24 PM
#43
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St. Jude Donor '05
the 180s can be ported, have you considered a converted LT1 intake ie the poormans mini? If youre putting boost to it work the runners over some and save a lot.
How much boost are you planning on running? know the L98s are 2 bolt mains. They can handle some but-
Wouldnt start changing anything due to a dyno sheet, take it to the track, how does it feel to you? Should run pretty strong.
That claimed 40hp will start where the TPI starts crapping out, not straight across the board.
What rearend gear do you have?
How much boost are you planning on running? know the L98s are 2 bolt mains. They can handle some but-
Wouldnt start changing anything due to a dyno sheet, take it to the track, how does it feel to you? Should run pretty strong.
That claimed 40hp will start where the TPI starts crapping out, not straight across the board.
What rearend gear do you have?
07-07-2018, 07:22 PM
#45
Team Owner
Pro Mechanic
LT1 Intake
Last edited by Tom400CFI; 07-10-2018 at 11:33 AM.
07-08-2018, 08:20 AM
#46
What do you guys do that have converted the TPI intake to the LT1 for thermostat relocation and dealing with head port matching (with reverse cooling on the LT1) and distributor location? Drilling holes and machining??
Just curious.
Just curious.
07-08-2018, 12:12 PM
#47
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St. Jude Donor '05
Most machine shops can weld it up, or David Frederick in the parts for sale secltion can do the whole thing.
07-08-2018, 02:07 PM
#48
Team Owner
Pro Mechanic
What ^he said. I believe Dave Frederick charges ~$300 to convert it, so you buy one like mine and you're into a "mini ram" on the cheap.
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Last edited by Tom400CFI; 07-08-2018 at 02:08 PM.
07-08-2018, 03:46 PM
#50
Instructor
Thread Starter
Thanks guys. If I decide to go forced induction I’ll put forged everything in the bottom end and run 12-15 psi.
That should push the dyno past 300 
07-08-2018, 05:02 PM
#51
Team Owner
Pro Mechanic
Interesting!
I remember this debate on mini ram vs. LT1 intake. Nothing was proven but was interesting dialogue.
https://www.corvetteforum.com/forums...t1-intake.html
I remember this debate on mini ram vs. LT1 intake. Nothing was proven but was interesting dialogue.
https://www.corvetteforum.com/forums...t1-intake.html
07-08-2018, 05:35 PM
#52
Race Director
Stock, L98's generate something like 200rwhp. That's + or - 10rwhp. So, the OP is asking about a 50hp gain with mods added. I understand the question of disappointment. Here are my thoughts:
Dyno: Didn't remember seeing a comment on the dyno itself. Different dynos read high/low. It's not THAT reliable unless you measured stock first (on the same dyno). Even then.
Heat: We're in summer. How much was heat a factor in the runs?
Porting: SLPs aren't much bigger than stock runners. Of all aftermarket options, they are smallest. Let's see how you ported them. If not a lot, that's my first vote for power left on the table.
Cam Orientation: How did you install the cam? Degree it?
Head Planing: You reduced the size of the 180's to 58cc(ish)? I did too...for the same reasons you probably did. Later, I learned this cuts down on flow...though (shrouding) though AFRs don't really have this problem. Probably didn't hurt but it's odd considering your goal to boost it. Seems you should have left them at factory 65cc.
Flow: AFR 180's don't have quite the low-lift numbers of the 195 which is as much a reason for choosing the larger head even WITH a long-tube build. Talk of head/intake mismatch isn't THAT big a deal. Again, 195's are better if top-end (track) speed is the goal. Best longtube 350 setup in this forum is member "TA" IMO. He made it to 325rwhp after stroking his similar 1990 setup. I didn't see his 350 hp number but he might have been 20rwhp better using similar heads. He used TPIS runners which I think are 15rwhp better than "stockish" SLP runners. They have 1/4" bigger tubes.
Injectors: Injectors are only a problem if they don't spray as good as new. More FP might help a bit but not a lot (if operating properly).
Mufflers/Exhaust: What size exhaust tubing? Are mufflers one step bigger than exhaust tubing (i.e., 3" with 2.5" tubing)?
Bottom line: You might have left 20rwhp on the table which have as much to do with intake porting as anything. Maybe the rest based on dyno, cam degree, injector performance (not size), and tuning. I wouldn't be surprised if a MR gave you that 40rwhp promised. Partly because you may not have an optimized longtube INTAKE setup though. Again, it seems odd you cut-down the 180s to stock bowl size if planning on boosting it. Guessing it's a few miles down the road? Porting (in) a longtube setup is everything.
Dyno: Didn't remember seeing a comment on the dyno itself. Different dynos read high/low. It's not THAT reliable unless you measured stock first (on the same dyno). Even then.
Heat: We're in summer. How much was heat a factor in the runs?
Porting: SLPs aren't much bigger than stock runners. Of all aftermarket options, they are smallest. Let's see how you ported them. If not a lot, that's my first vote for power left on the table.
Cam Orientation: How did you install the cam? Degree it?
Head Planing: You reduced the size of the 180's to 58cc(ish)? I did too...for the same reasons you probably did. Later, I learned this cuts down on flow...though (shrouding) though AFRs don't really have this problem. Probably didn't hurt but it's odd considering your goal to boost it. Seems you should have left them at factory 65cc.
Flow: AFR 180's don't have quite the low-lift numbers of the 195 which is as much a reason for choosing the larger head even WITH a long-tube build. Talk of head/intake mismatch isn't THAT big a deal. Again, 195's are better if top-end (track) speed is the goal. Best longtube 350 setup in this forum is member "TA" IMO. He made it to 325rwhp after stroking his similar 1990 setup. I didn't see his 350 hp number but he might have been 20rwhp better using similar heads. He used TPIS runners which I think are 15rwhp better than "stockish" SLP runners. They have 1/4" bigger tubes.
Injectors: Injectors are only a problem if they don't spray as good as new. More FP might help a bit but not a lot (if operating properly).
Mufflers/Exhaust: What size exhaust tubing? Are mufflers one step bigger than exhaust tubing (i.e., 3" with 2.5" tubing)?
Bottom line: You might have left 20rwhp on the table which have as much to do with intake porting as anything. Maybe the rest based on dyno, cam degree, injector performance (not size), and tuning. I wouldn't be surprised if a MR gave you that 40rwhp promised. Partly because you may not have an optimized longtube INTAKE setup though. Again, it seems odd you cut-down the 180s to stock bowl size if planning on boosting it. Guessing it's a few miles down the road? Porting (in) a longtube setup is everything.
07-09-2018, 01:12 PM
#53
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That seems to be the consensus. I’ll have to go with a mini ram since the super ram is impossible to find anymore. I probably should have gone with AFR 195,s as well but I’m not sure I can justify tossing the 180 elims. Can these heads be ported to give me what I need?
07-09-2018, 01:51 PM
#54
Drifting
07-09-2018, 01:53 PM
#55
Drifting
That seems to be the consensus. I’ll have to go with a mini ram since the super ram is impossible to find anymore. I probably should have gone with AFR 195,s as well but I’m not sure I can justify tossing the 180 elims. Can these heads be ported to give me what I need?
07-10-2018, 10:33 AM
#56
Melting Slicks
Possibly a silly question possibly not, what are the goals and budget? Without a goal and budget this can turn into a project that never ends. If something does not give what you think it should be meets the stated goal then a success rather than an endless quest that will never be done.
07-10-2018, 03:04 PM
#57
Instructor
Thread Starter
The goals are constantly evolving and the budget is not fixed. Had I known what I know now I probably would have done an ls swap.
Current goal is a 10 second car but the original goal was a modest improvement. Once I get a 10 second car i’ll Probably want a 9 second car.
I just can’t justify tossing what I have and starting again.
Last edited by fast.asleep; 07-10-2018 at 03:18 PM.
07-10-2018, 03:17 PM
#58
Instructor
Thread Starter
Doing that, porting the 180’s and adding forged parts is probably what i’ll do before I add the blower. Depending on $$ my other option is pushing 6psi through my current bottom end.
07-10-2018, 04:05 PM
#59
I have been down this road before but long ago; 2002-2003. I still have the car. It’s a one off 85 with the 91-96 rear bumper Gen I SBC with a nice exhaust note and runs 12’s with street tires and ZF6 tranny...love the car along with the white face Autometer gauges...It’s a C4 that GM never made......However......
Going back to what you said....I don’t know I would do this project today....why????
I had no idea muscle car era 2.0 was going to the levels we are seeing today....technology has has grossly improved in the new cars and they do everything so efficiently with a huge aftermarket. Don’t get me wrong, this car will stay with me since it’s a quality build....but If I were you, buy an LS with a whole car wrapped around it. Computers and televisions from the 80’s and 90’s were great at that time, but could you imagine trying to convert one to your big screen HD set or get your 1985 Macintosh to perform as well as your small smart phone???
Going back to what you said....I don’t know I would do this project today....why????
I had no idea muscle car era 2.0 was going to the levels we are seeing today....technology has has grossly improved in the new cars and they do everything so efficiently with a huge aftermarket. Don’t get me wrong, this car will stay with me since it’s a quality build....but If I were you, buy an LS with a whole car wrapped around it. Computers and televisions from the 80’s and 90’s were great at that time, but could you imagine trying to convert one to your big screen HD set or get your 1985 Macintosh to perform as well as your small smart phone???
Last edited by 856SPEED; 07-10-2018 at 04:09 PM.
07-10-2018, 04:13 PM
#60
Melting Slicks
If you want a 10 second car build a 9 second car add 20k at least to the budget and plan on maintenance travel and lots of seat time unless you race 9 second cars already. Needs a cage and back half at least and aftermarket electronics or carbs or a good turbo. Not a cheap date and yes everything you have done is money down the rabbit hole.