SpartanSV

The fact that I've reached this point without asking a single question is a testament to the brilliance that is archived on this forum. Thanks to those who have contributed.

I recently completed the drive train build on my 97. Fully rebuilt NA8 with ebay rods, stock NA8 pistons, DIY log manifold with 2.5 downpipe to a 3 inch magnaflow cat and the MT approved magnaflow muffler, MS3x built to brain's specs w/ flex fuel sensor and realtime baro correction, id1050x's, 2871 churbo.

I'm posting now because the car feels disappointingly slow. Virtual dyno seems to be a finicky bitch but around 200 hp at 19 psi is about the best I can muster. The car will always hook up when rolling on the throttle in any gear at any speed even on 185 chinese all seasons.

I realize I'm well past what the stock ignition system should be happy with, but the car seems to pull smoothly and to my inexperienced eye the logs reflect that.

Am I expecting to much and failing at VD usage, or is there something very wrong with my setup? Botched timing belt install?(will check tomorrow as it just came to me)

Current tune and typical 4th gear pull to 5k log attached. VE in lower boost cells obviously needs help. I also have 100% boost control duty and can't make any more boost on what is allegedly a 10 psi spring.

ryansmoneypit

iTrader: (6)

nothing jumps out at me, but thats slow. you should be twisting those 195's right off in 3rd.

Ryan_G

iTrader: (8)

You need to double check the size and health of your turbo and probably do a compression check on the engine. Getting only 200hp at 19 psi with a turbo of that size means something is definitely wrong.

borka

iTrader: (1)

Post a screenshot of your ignition table.
Did you time your engine to 10 degrees when you first installed the megasquirt?

albumleaf

iTrader: (7)

^^
Ignition table is in the MSQ and looks fine.

You're also running suuuuuuuuuuper rich on tip-in. May want to check your AFR sensor calibration as well. I assume your MS readings match your gauge? When I installed my setup initially I was running so rich that it was drowning the car in fuel under boost (sub 9 AFR). Felt a ton better after getting it back in the 10.5- low 11 range.

One other good sanity check would be trigger angle & making sure you're actually using the ignition table & not a static 10 or whatever you used for setup.

sixshooter

iTrader: (12)

I had that turbo on a stock na8 with iron log manifold and made 200whp at 10psi.

Double check timing belt. If it is off a tooth or two it can cause what you are seeing.

andyfloyd

Definitely check the Cam timing as others have stated. How does off boost response feel, does the car feel sluggish when out of boost? Even with terrible cylinder compression you would be making more than 200whp @ 19psi. Thats a pretty large turbo even with the log manifold it should be 300whp, especially with the e85. Just for reference I just completed my build and 13psi on a gt2560 and a FM log manifold I spin all through second gear and sometimes in 3rd with somewhat crappy 195 hancook's.

Is there possibly an exhaust restriction somewhere?

sixshooter

iTrader: (12)

There is actually another thread currently going where cam timing was off a tooth and went from around 10 psi to 19 PSI with no performance gain. I believe the subject line has something to do with Boost Spike. Since boost is just a measure of back pressure in the system you can easily have it go up when things aren't flowing correctly.

SpartanSV

Ignition timing was setup properly when the engine went back in. Ignition table is from brain's base map with no changes. Timing definitely isn't locked.

Wideband matches TS.

Other than being slow the engine seems to run fine. Starts easily, doesn't smoke, driver's side valve cover port is VTA through a filter and the filter is dry. I can do compression and leakdown tests if the cam timing check is fruitless.

Car feels pretty slow everywhere but I haven't driven a healthy NA to compare it to.

I just built the exhaust and spool seems to be exactly what it should be for this setup so I'm doubting it's a restriction issue.

Thanks for the feedback so far. I'll check cam timing tonight and report back.

andyfloyd

good luck man I hope its something very simple.

SpartanSV

The timing results are in.

Here is cam timing with engine at TDC. I verified TDC matches the crank with an object in the #1 spark plug well.







This is the crank at TDC.




This is the positioning I see with ignition timing fixed at 10 degrees BTDC.




Anyone see anything wrong? I sure don't.

SpartanSV

I also logged a cold start to check vacuum at idle. ~39 kPa at 1025 rpm. Seems reasonable.

ryansmoneypit

iTrader: (6)

Nevermind

ryansmoneypit

iTrader: (6)

My next guess: Pully on cams indexed on the cam incorrectly. Easy to do, each one has 3 slots.

SpartanSV

I thought of that too. Cam lobes are oriented correctly.

borka

iTrader: (1)

Do NA's have a timing plate behind the crank pulley? i know on NB's you can put that plate backwards and it will throw the timing off, as the teeth in the wheel will pass the crank sensor at the wrong times.

nitrodann

Do you have toothed belts where ribbed belts go?

Dann

sixshooter

iTrader: (12)

?Que?

SpartanSV

Nope. They're some fancy ****.
Continental

SpartanSV

They do have a plate (NA8's at least) but I verified ignition timing is correct. That should have ruled out an issue like that unless I'm misunderstanding.