JimVR4 95 Spyder Engine Rebuild

**Jimvr4** · 03-20-2014, 12:23 AM

I read that the gap should be as large as possible to get a complete burn under low load and still avoid blowout under high load. But with an ignition amplifier you can run bigger gaps all the time and make more power without blowout.

**kywhitelightning** · 03-20-2014, 01:56 AM

Originally Posted by Jimvr4

Joined the 400WHP today. I'm still learning how to tune. I'll share my chart here with 100 octane. I reverted to the timing table I had just previous but didn't take away any fuel. As a result it's pig rich (10 AFR) when boost kicks in and only leans out when I crank up the boost. I pretty much maxed out the 560s with this tune so I expect I could pull fuel to about 11 AFR and probably get close to 450WHP on 100. I still have the rev limit at 7000, might turn that up to 7500. The car seems to break up slightly at the top end, guessing it is spark starting to blow out. Is that even likely at my power level?

Attachment 6551

Make sure you are temp and baro correcting your VD graphs. They can be deceiving if your conditions are different than the SAE default in VD. I have seen up to 50AWHP differences with and without the correction. Just depends on how far you are from default.

Originally Posted by Jimvr4

I'm posting up some detailed charts from my best pull so far. This was a 412 WHP pull with 0 knock. It looks very smooth in Virtual Dyno however at least at the top of the pull I could sense some slight hesitations like possibly spark blowout. I was also running close to 100% IDC if I can believe the logs. I know my tune is way too rich and Abram said I should be able to get to > 500WHP on my hot wired Supra pump and 560 injectors based on his experience with the Supra fuel system. So I don't think I am out of fuel up top. As I said I have 0 knock and my wideband is reading less than 12.

What's bothering me is two things. First my boost is not as stable as I would like. I'm seeing at least ±3 psi ripple across the rpm range. I've gone back and looked at some early logs when I was just wastegate and I also see ripple though maybe not as much. So the first thing I'm wondering is whether those stiffer Dr Weldin wastegate springs are actually a source of trouble. Because they are so stiff I think the dynamic performance of them is much slower than the stock springs would be. My AVC-R boost controller has a feedback setting I can play with to see if I can tune around this so that's what I will try first.

The second one is the hesitation up top. I'm using range 7 coppers gapped to .032. I don't think I want to gap them any lower with my crappy 91 octane so I was thinking this is a good time to try out my voltage booster idea to pump up the coil voltage to 15 or so.

Attachment 6564

.030" should be all the smaller you will need for a plug gap. I ran that for years with my 19T setup >500AWHP. The heat range of the plug in my experience will not affect it's ability to arc under power, it will only affect the tip temp which you should be fine with. Wonder if you might be experiencing rich misfires up top?

Looking at the graph you have posted, your IDC calculated seems to be pretty close as best I can tell. Looks to be near 17ms on IPW at near 7000RPM (raw numbers are easier to decipher than the graphs). That's 99%. Pull some fuel out and see if a lot of things change for the better. You may be pleasantly surprised.

Jeff

**Jimvr4** · 03-22-2014, 05:47 PM

Originally Posted by kywhitelightning

Make sure you are temp and baro correcting your VD graphs. They can be deceiving if your conditions are different than the SAE default in VD. I have seen up to 50AWHP differences with and without the correction. Just depends on how far you are from default.

.030" should be all the smaller you will need for a plug gap. I ran that for years with my 19T setup >500AWHP. The heat range of the plug in my experience will not affect it's ability to arc under power, it will only affect the tip temp which you should be fine with. Wonder if you might be experiencing rich misfires up top?

Looking at the graph you have posted, your IDC calculated seems to be pretty close as best I can tell. Looks to be near 17ms on IPW at near 7000RPM (raw numbers are easier to decipher than the graphs). That's 99%. Pull some fuel out and see if a lot of things change for the better. You may be pleasantly surprised.

Jeff

Jeff, thanks for the reply. I made some more runs today and corrected for temp and baro and unfortunately my power is lower than I thought. My 412WHP run came out to 396WHP after correction damnit

I pulled the front plugs and had a look. The ground straps were striped from running three different timing profiles so far. It looks like the current profile is optimal with the lighter band occuring at the curve on the ground strap. The base ring indicates a rich tune as expected. Gaps on the front three were .033 to .036 so I closed them to .030. I didn't pull the rears and adjust those yet.

I pulled 8% from the 1600Hz VE entry and did a half dozen pulls. Some of them seemed to feel cleaner up top than before. Logs show AFR in the 4000-5500 rpm range went from 9.7 up to 10.2. Up top it went from 10.4 to 10.9. I believe I can pull another 5-8% and keep AFRs below 11.5 up top. IDC went from ~100% down to 94% up top.

I will pull the rear plugs and gap them to .030 and pull out some more fuel up top. I also forgot to go back in and change the feedback speed on my AVC-R boost controller as I think it may be overcompensating.

**OhioSpyderman** · 03-22-2014, 06:56 PM

Jim, you are miles above where I ever wanted to be....I just wanted to remind you that our cars weigh a WEE bit more than stock, so don't expect the same results....

Matt M. will probably chime in...

Bob.

P.S. Your work since your unfortunate problem has been nothing short of AMAZING!!!!!

**kywhitelightning** · 03-23-2014, 04:24 AM

Virtual dyno will correct for both driver and vehicle weight but it really won't make too much of a difference in the power VD will spit out.

Jim, what fuel are you using? It seems to me you have a lot left in the timing department to go which will also lean the AF mix out a little, as long as you are still running this timing map. http://www.3sgto.org/attachments/tun...ce-timing2.jpg

Take your time and for sure stay in your comfort zone as I will only make suggestions and am in no way attempting to pressure you to do something that you don't want to. BTW, 396 is close enough to 400 for me, lol. Congrats and best of luck pushing it further.

Jeff

**Jimvr4** · 03-23-2014, 11:33 AM

Originally Posted by OhioSpyderman

Jim, you are miles above where I ever wanted to be....I just wanted to remind you that our cars weigh a WEE bit more than stock, so don't expect the same results....

Matt M. will probably chime in...

Bob.

P.S. Your work since your unfortunate problem has been nothing short of AMAZING!!!!!

Ha ha, thanks buddy

I've surprised myself with how far I've gone and it has been a huge learning experience. I never worried about getting in too deep with all the support on the forums and I've been fortunate to have a good weather unmolested car to start with.

I really don't need to go much beyond the power level I have now, just want to clean up the misfires up top and I'll call it good

**Jimvr4** · 03-23-2014, 11:49 AM

Originally Posted by kywhitelightning

Virtual dyno will correct for both driver and vehicle weight but it really won't make too much of a difference in the power VD will spit out.

Jim, what fuel are you using? It seems to me you have a lot left in the timing department to go which will also lean the AF mix out a little, as long as you are still running this timing map. http://www.3sgto.org/attachments/tun...ce-timing2.jpg

Take your time and for sure stay in your comfort zone as I will only make suggestions and am in no way attempting to pressure you to do something that you don't want to. BTW, 396 is close enough to 400 for me, lol. Congrats and best of luck pushing it further.

Jeff

I've been running 100 octane since I filled up a week or two ago. I'm down to around 1/4 tank now and I'll say I've set a new personal record for fewest miles per gallon

The timing chart you linked is still what I'm still running. I know there is room to add timing with 100 but I'll have to dial it back again for 91. At the time I added the 100 I wasn't thinking how much I would have to change everything to take advantage of the additional octane.

I still have the EVO MAF and DSM SMIC to install. The intention was to see how far I could push the 91 and I'm still not sure if those will make a difference. I suppose they might if my tune is knock limited on the 91.

Still I will be happy with 400 if I can get rid of the misfires up top.

**kywhitelightning** · 03-23-2014, 01:52 PM

I don't forsee you being octane limited until at least 425-450WHP even on 91. If you stick to your modest goal, you will maintain a smile for a VERY long time. Parts life will be great. It always seems though, that the power itch strikes and we always push for more to find the edge.

Jeff