just finished my homebrew kit, seems a little slow compared to another nb2 i turboed with a t3, I know different turbos and setups make different amounts, but mine seems very low.
stock block vvt 2002
t25 .64 sr20 turbo , 2.5" ic piping, cast mani, 2.5" straight exhaust with a stock muffler, rx8 yellows (backups bc my 1000ccs sketched me out) stock fp, electronic boost controller. full e85.
baro is 89kpa here (north tx), map line is top of intake manifold, tee'ed with my cruise vacuum line.

im hitting around 11-12 psi max, slowly tapering down. I'm running out of injector around 6000rpm at that level.

Anyway I did lots of 3rd gear pulls today, ran them through virtual dyno, got an avg of 165hp (see ss) best road i could find, also did a 2nd gear pull but it might have spun.
Just wanted to know if anyone has made similar powered pulls at this boost level. I had very aggressive ign timing, and changed to a trubokitty basemap and lost maybe 5-10 hp, I didnt hear knock on that aggressive map on e85.

basemap




aggresive.


and virtual dyno runs:: 3rg7 and 3rdg 8 are basemap for ignition timing, runs before that are aggressive timing. maybe im overshooting sweetspots on both? my second set of det cans gets here tmrw to listen and tune it properly, just not sure if im missing something large.

 

Bump to add - i rechecked base timing, took off muffler, lowered boost, changed vvt settings, no dice

going to check for boost leaks tonight as best i can. I want my missing horsepower lmao

 

fixed a large boost leak, now i found a small vacuum leak between the tb and intake mani, but still missing my horsepower, took it up to 14psi and still made 160hp on vd. Even put the bigger injectors in. Will keep looking

 

compression is good!! Thank god, 155,150,155,155 warm.
found my catch can leaking air, but still confused. Added 2 degrees of timig and made 13hp on vd, but also upped boost by a pound

 

alright! Redid mechanical timing, photos attached.

t



i found something interesting? (Maybe) the timing marks on the pulley dont line up when the crank gear mark is lined up. Does this mean its overly advanced or retarded from the getgo? When i lock the timing at 10 degrees and check with a timing light, the mark on the left lines up with 10btdc on the plastic. So it shows up as correct. Im grasping at straws here atp. Someone please induce insight.

 

your timing cover looks bent/warped.
Imagine the front edge of the cover parallel to the pulley. If that was actually straight the marks would line up better. From the looks of it when you lock the ignition timing to show 10 degrees you are likely only about 6 degrees. In other words from the pic it looks cover is bent enough to be retarded about 4 degrees when checking ignition timing. Get you a piston stop to verify exactly has much its off.

 

if thats the case ( ill check when off work) this would mean add 4 to the trigger angle to accommodate the error with base timing correct?

 

confirm tdc with a piston stop first, then adjust offset as needed. You may find the elastomer in the balancer has broken down some over the years and allowed some movement in the outer ring as well. Its always a good idea to confirm tdc marks on balancers when doing ignition timing work.

 

i see, i wasnt grasping your words well, but turns out i think i did this, telescoping magnet in first plug hole, found where it stopped moving up, marked tdc on the pulley where the mark should be, then set base timing with that (removed 4 degrees to make the mark at 10btdc) though im not entirely sure i went in the right direction with the spark, it made 110hp on 10psi after that. So i set it back to 0. I want to be a little more scientific about it and think a little longer on the logistics, they didnt make the most sense at the time because i was hot and tired lmao.

 

(If) the timing cover marks are shifted to the right 4 degrees and (if) the balancer marks are true, 10 degrees btdc should look as 14 btdc on the cover as it is, If that makes any since. So the leftmost hash mark on the pulley will be on the 2nd mark on the cover to the left of the 10 degree mark of the cover with a timing light when locked at 10 btdc. This will show as 14btdc when in fact its really 10btdc.

 

Whatever i lock it to, shows up perfectly on the pulley relative to the marks, so 14 shows 14, 10-10 ect. The only place its off is when its static and the crank gear is at tdc.

 

Yeah that proves that the ecu can move timing properly, but your cover is not right. Lock timing to 10, then adjust offset until pulley reads 14. Because 14 is that cover’s 10.

 

exactly..... curly said it much better LOL......

 

This is what i ended up with, fixed the trigger offset (+4) so now the "10btdc" mark is at the 14 degree btdc mark at 10 degrees locked. This helped, though Ive still been playing with things, listening for knock on my det cans, this table and 15psi peak made 191 according to vd. I am going to order a leakdown tester as i am losing my mind trying to think this through. Maybe its a combination of everything? Altitude, exhaust/turbo, and poor tune? I just keep going down the "dynos and timesheets" wishing they were me haha. I cant weigh the car atm, though its probably lighter than stock given its rust and lack of stock items. I have a 2.5" straightpipe all the way back until the axleback stock muffler i grabbed from a friend. I was planning on adding timing until it stopped making power, as you're supposed to for peak power anyway, but I cant get good pulls in third without spinning my worn down falkens. 4th is a bit scary. I need insight, any, good or bad, even "you're a ****** loser and have no idea what you're doing." atp. Looking at the specs of my turbo, it seems it could also be a big factor in my issue.
compressor: .42 ar 37.8 inducer 59.7 exducer 40 trim turbine .86 ar 52.9 inducer 45.47 exducer 73 trim.

 

Can you post the tune and a log now? Sounds like you’re making progress if you went from 160 to 110 to 190. What are “worn down” falkens? What tire? What year manufactured? They’ll only get worse as you fix the tune

 

That is a peewee turbo. You say 15psi but is it still falling at high rpm's? That little turbo is likely only going to make a little over 200 at altitude even if it held 15psi at peak rpm. Also e85 likes timing.

 

Heres where I'm at.


Red is the trubokitty base vvt ignition map with the trigger offset fixed + 2 degrees above 100kpa.

Blue is 12.8 max boost, +3 above 100kpa on ignition. This barely puts 200kpa at 13-14, and I dont even hit 200 kpa. Maybe I leave ignition alone, and add more boost since the compressor is flowing very little comparatively?

I uploaded the logs of those vd runs, labled them as best i could. The tune provided has the ignition map I made the 178hp pull on. Think the boost duty is also the same.
the falkens im on were old autocross tires that came with the wheels I bought from a buddy. They used to be worn, now theyre bald. I'm aware theyre only getting worse, tires are on the top of the list. I can hook on a road around here thats perfect, except its a quiet road that is home to the police station for this side of town. It also has a 45mph limit smh. I will continue to try and improve this horsepower number.

 

I got it to hold that by tapering boost duty, though my goal was inital spoolup to 12, then taper to 15, didnt work. But yes I knew e85 takes some extra timing to make mbt, im just not sure how far into it that is.

 

looks like you are starting to get a little closer to what you should expect with that small turbo at elevation. Should be feeling a bit better than before.
You would be shocked at my timing. But I'm running very low compression and a much larger turbo setup.

 

You won’t knock with e85, you’ll just stop making power, so go ahead and try 6-8 degrees and see if that’s your limit, but after reading your turbo specs, yeah that guys pretty tiny, are there a lot of ~230-240hp sr20 dyno charts in the spoil thread? Been a while since I’ve looked. If they’re 210-220, you’re probably at or near your limit at altitude.