tuning a CA18DET

[GZL-19T]

hey i was wondering what is the best air fuel raito to have my CA running at.. it has been fully rebuilt with forged pistons and 1.5mm headgasket and BB turbo.. and the timing.. should they be the same all through the rev range or is it better to change it around ?

[float_6969]

When you're underboost you want to be at 12:1. I'm not sure about the timing.

[Def]

You definitely want to RETARD timing under boost. 0.75 degrees/psi of boost is a pretty good rule of thumb. So if your base timing is 25 degrees at zero vacuum/boost - then you'd be at 17.5* of timing at 10psi of boost.

These numbers are just theoretical, I don't really know what works well on CA's. I think the factory SR20DET computer runs about 14-16* of timing at full load in the upper RPMs if that helps.

[float_6969]

Def, I love the Avatar man. I was LMAO when I figure out what it was!

[GZL-19T]

12.1 is that a bit rich

[biosehnsucht]

Run rich to save the *****, lean out to take her out!

[Nismo1182]

12.1 is fine.

[Def]

Def, I love the Avatar man. I was LMAO when I figure out what it was!

Glad you got a kick out of it.

[paul_s13]

Between 12.5-12 : 1 is best depending on what fuel you are using, as for timing, as much as you can get away with before it starts to detonate really!

[Jezz_s13]

Fook me it's Paul!!!

[boost_boy]

You don't want your total timing to get past 28* because after that is cranked ringland country.

Dee

[paul_s13]

Fook me it's Paul!!!

Ello mate, hows the car going?

[Jezz_s13]

Ok actually for a change LOL, just planning a mental attack on it, Pauter rods, huge turbo and 950cc injectors blah blah...looking for ~470-500rwbhp.

[GZL-19T]

fuel is like 98%.. so what would be to set it at if i wanted to have it the same all the way through...

when i change gears now it takes very long to come on boost like 5 sec.. some times more but if i hold it in the gear and then give it its ok.. hmm

[boost_boy]

Quote »when i change gears now it takes very long to come on boost like 5 sec.. some times more but if i hold it in the gear and then give it its ok.. hmm[/quote] What are your turbo specs? I always warn people about really huge turbos on the CA especially when it's just a street car, but no one listens (Good for them). But if you have the stock T25, I would suspect the turbo is failing if everything is in good working order.

Dee

[paul_s13]

Ok actually for a change LOL, just planning a mental attack on it, Pauter rods, huge turbo and 950cc injectors blah blah...looking for ~470-500rwbhp.

Kewl, what did you do for a manifold in the end?

[GZL-19T]

i got a BB T28 and has been hi flow'd ...around 380hp

it did not use to do it.. its all brand new ran it in 1000 ks all good.. took it for a run up the coast 2 hrs each way.. was sitting on like 4k+for some time and its done it sence...

could it be that its a after market computer and it needs to be tuned again sence its been run in more ?

[Jezz_s13]

making a top mount one.

[paul_s13]

making a top mount one.

Your making one? Last time i remeber a post of yours you didn't have much confidence in your welding abilities, practice makes perfect though innit!

Top man if it works.

[boost_boy]

Quote »i got a BB T28 and has been hi flow'd ...around 380hp[/quote] When does your boost come in? What size back housing do you have? If it's one of the S15 thinga-majiggies, then this would explain some of the hesitation or lag. I think your situation is ideal for others to learn from. Your turbo is not what the factory prescribed for this motor. The T25 and it's .48 housing is what the factory issued for the CA18DET. S15 carries a .64 housing (IIRC) and you will encounter some lag from it. Whereas the SR20 and bigger engines flow enough CFM to get these turbo moving at lower rpms.

Oh yeah Jezz_S13 and Paul_S13 you guys are officially thread jacking:ylsuper

Dee

[GZL-19T]

boost comes on at 4g.. if i dont give it just cruze from 1st to 2nd and then give it when its in 2nd its fine.. its just when im giving it all and change qhick and put back on it will boost to like 3psi and take so long to get to like 7psi.....like to 6g rpm..

do u get what i mean?

[boost_boy]

Quote »do u get what i mean?[/quote] I sure do! that's what happens when you step up to a bigger turbo. Answer this question, what did you do with the butterfly assembly on the intake manifold? Did you leave the butterflys open by not attaching a vacuum hose or do you have vacuum on the actuator pump?

Dee

[GZL-19T]

they are always open.. i dont have any vac lines they got removed with microtech was put in..

i put picks up if u can remember..

i have always had a T28 on my CA i just put a BB one on when i did the rebuild.. it did not use to do it tho

[Jezz_s13]

true true but we are technically talking about CA tuning. I'll shut it/zip it, now.

[boost_boy]

Quote »true true but we are technically talking about CA tuning.[/quote] Tell me anything! I have a soft-spot for my fellow CA brethren:D

Dee

[GZL-19T]

hmm not too sure.. i might get it dyno tuned tomorrow

might be able to fix the problem then...

got my rx7 450cc in the mail the other day.. thanks gerry .. looks like they fix right in.. plug is the same and all.. they are the brown top ones

[boost_boy]

You're using the microtec, right?

Dee

[GZL-19T]

yep with the bosch coils

[boost_boy]

The few people I know that are using the microtech on the CA18 are aborting them. I would defintiely be checking the timing.

Dee

[GZL-19T]

ah ok.. i have not herd anything bad about the microtech.. what have u been told / come accross ?