1st dyno w/ 7m installed

[moorman]

First #'s with the 7m:

updated 250rwhp/266rwtq

Current setup is:
rebuilt block bored .020
toyota .020 oversize pistons
8.9:1 comp ratio
cometic HG (surfaces prepped to 17.3RA)
no other head work, should've P&P'd
wastegate shimmed w/ 2 washers (roughly 9psi)
base timing 12deg
91octane pump gas (yay! - the 6m-T required race gas)

still have slight irregular miss & top end could use some leaning. I'm considering grabbing the MAF-T Pro rather than installing the AFC. If I can just cure this *$&#$*(@! irregular miss so I can get my car legal, I'll start pushing to boost more around 15-18psi.

 

[Adjuster]

Misses only on the top end?

My guess is your plugs or wires. (If they are new wires, what are your plugs gapped at?)

.28 is the best setting for any plug at higher boost I've found on the 7M engine. (I know that "stock" is wider, but wider causes misfires.)

Try the .28 gap. It has cured many misfilres at high rpm/boost, not just my own car.

 

[Enraged]

nice numbers! if you want "true" hp numbers and not dynojet numbers, tell your dyno operator to set X to 0, not 1.170.

 

[moorman]

Misses only on the top end?

My guess is your plugs or wires. (If they are new wires, what are your plugs gapped at?)

.28 is the best setting for any plug at higher boost I've found on the 7M engine. (I know that "stock" is wider, but wider causes misfires.)

Try the .28 gap. It has cured many misfilres at high rpm/boost, not just my own car.

The miss is most discernable at part throttle. At WOT there's too much noise to tell, and I can't feel any hesitation.

What I've tried:
disconnecting temp sensor (no change)
New plugs - autolite 3923
new plugs - one step warmer
shorter & longer plug gaps
New plug wires
new CPS
new TPS
new alternator
injectors have been cleaned & tested, 3 were replaced due to leaking, then all were cleaned & tested again

coil pack was swapped with known well running mk3 (no change)

ignitor was swapped (no change)

all intake piping was re-made and new IC installed (with exception to my pvc fender pipe which I tested to show no leaks

vacuum at idle is steady at 19.5"HG
boost leaks cured, car now pulls roughly same as my 6m-t did, wastegate shimmed w/ 2 washers

quadruple checked all vacuum hoses, even tried blocking off all vacuum ports entirely

double checked all ground straps and cleaned their contact points; block to neg batt terminal, head to firewall, coil to head, bell housing to chassis

dropped stock FPR and installed aeromotive FPR (intended to anyways)

 

[Justin727]

not bad at all

 

[moorman]

nice numbers! if you want "true" hp numbers and not dynojet numbers, tell your dyno operator to set X to 0, not 1.170.

Good info! I've always felt the #'s from this particular dyno to be inflated. ....which suddenly jogs my memory.... I went through a similar process years ago with a different Dyno Dynamics shop (which has closed down) and digging up the old data sheet, I see it too has X=1.17. It was when I first put a turbo on the 5m and felt my #'s too high. All the dynos I'd seen of a 5m+T fell between 205hp & 215hp, and my dyno came out w/ 249. A new run at a Dynojet shop gave me 212hp. Going back & doing the math works out perfect, dividing 249 by 1.17 = 212. I thought my results seemed a little high, but since there's such variability in all the 7m dynos I've seen, I just swallowed it w/ a smile. :beer:

I'll plug the #'s into excel and update. Tomorrow I'll go back to the shop and make them reprint my charts to have something that looks more official.

 

[Enraged]

ya, our local dyno shop has a dyno dynamics, and they give 2 sheets, one with X = 0 which is true hp, and one that has x = 1.17, which gives you dynojet style numbers. they suggest the dynojet numbers are purely for comparison.

 

[VanSupra]

ya, our local dyno shop has a dyno dynamics, and they give 2 sheets, one with X = 0 which is true hp, and one that has x = 1.17, which gives you dynojet style numbers. they suggest the dynojet numbers are purely for comparison.

I was under the impression that the Dyno Dynamics gave the higher reading, atleast over here anyways..I dunno..

 

[Enraged]

a turbo lexus dynoed recently and with no correction was quite a bit lower than the dynojet he dynoed on last time. so i dunno, im no expert, just passing on what my freinds shop said.

 

[VanSupra]

I guess they're all different for whatever reason. I'm far from an expert myself. But in Kelowna I dyno'd on a mustang dynomometer and only made 349rwhp @ 12lbs and those guys were quite adamant that their dyno was correct. The day before going up there I dyno'd 427rwhp @ 12lbs Dynojet 248c. But I know the mile/hour doesn't lie. Gotta get to the track.

 

[Enraged]

ya, i know a dynojet will always read high (hence why alot of the *cough* mkiv big singles *cough*) like them...

 

[Adjuster]

Ok, new plugs, but what is the gap set at? (IF you did not gap them, they are all wrong out of the box. Pre-gapped is a joke.)

Set the plug gap to .28 and it will likely cure your high end miss. (Even at part throttle, or just barely into the boost.)

 

[VanSupra]

ya, i know a dynojet will always read high (hence why alot of the *cough* mkiv big singles *cough*) like them...

Well those are the guys we're after(almost an impossible task), but run'em down with old school..

:naughty:

 

[SupraMario]

mmm, thats nice,
this car would be an auto-x beast.

 

[moorman]

Ok, new plugs, but what is the gap set at? (IF you did not gap them, they are all wrong out of the box. Pre-gapped is a joke.)

Set the plug gap to .28 and it will likely cure your high end miss. (Even at part throttle, or just barely into the boost.)

Yes, all plugs get manually gapped (it's in my list, "shorter & longer gaps") The miss isn't a high end miss, it's most notable at part throttle (well before boost begins) but it's only slight. My passengers can't feel it, but since I know what I'm feeling for, I can tell. It's slight enough that I'd be willing to live with it, but the smog tests aren't. HC is quite high, but all others are well within passing range.

Judging by the irregularity of the miss (it's always there, it's just an irregular cadence) and the smoothness of my chart, I'm betting it isn't present at WOT.

 

[psifactor]

very nice power curve. I like how your tq basically stays the same unitl 5200rmps. Most 7m that i have seen will have a tq jump that quickly falls off. I'm assuming you have 3' dp and exhaust?

 

[moorman]

very nice power curve. I like how your tq basically stays the same unitl 5200rmps. Most 7m that i have seen will have a tq jump that quickly falls off. I'm assuming you have 3' dp and exhaust?

Thanks. Yeah, 3" from the hot side all the way back (suprasport elbow).