How much should I push it to?

[ssms5411]

I'm getting ready to dyno the car in a few weeks,I will do a N/A run and I was thinking of doing a .055 nitrous jet with a .024 fuel (on my wideband 12.0 A/F, zero KR at 25 degrees timing) and a .063 nitrous jet with a .028 fuel, haven't ran this yet on the street to know if any KR. The last one I was going to try would be a .071 jet with a .032 fuel. I'm going to add 5 gallons of 100 unl. oct. My mods are in my Cardomain site, look in profile. Also my KR sensors are reduced 40 % using the resistor method, been running that method for 3 years so I know it works. Also since I haven't dynoed with a A4 before do I leave the car in overdrive and just get up to my 3rd gear and then go from 2000 rpms? I still have the stock springs so my cutoff is 5700 rpms. I have a set of Comp 105's springs with the steel retainers and locks also will be switching out the light weight pushrods with some Comp 5/16 Hi tech ones once I recieve them. Do you guys think I should wait to do the dyno until I do the springs and etc. Just looking for some feedback. The car runs great replaced plugs about a month ago with some fresh TR6's gapped at .035, running royal purple in the engine and rearend. Tranny has I believe the Dexron VI in it. Kind of dopped up right now so I hope this makes since. Let me know what you think on the size of shot and if I should wait until I do the top end (also will be keeping stock rockers? Thanks for your feedback, Steve

[bigbrian442]

Re: How much should I push it to?

It's normal to pull timing when spraying nitrous. 2 degrees for every 50 HP. 25 Degrees is already a lot of timing for a 3.8. My 98 gets knock retard if I try to go over 21 degrees on 92 octane and the knock sensors are desensitized through the PCM 50%. Ask your dyno operator but locking the trans in 3rd gear is normal and if you have a stall locking the converter give you better numbers. Don't hit the bottle under 3000 to avoid backfires.

[Shodown]

Re: How much should I push it to?

It's normal to pull timing when spraying nitrous. 2 degrees for every 50 HP. 25 Degrees is already a lot of timing for a 3.8. My 98 gets knock retard if I try to go over 21 degrees on 92 octane and the knock sensors are desensitized through the PCM 50%. Ask your dyno operator but locking the trans in 3rd gear is normal and if you have a stall locking the converter give you better numbers. Don't hit the bottle under 3000 to avoid backfires.

Trust me, he knows all this ;) lol

Im excited to see the numbers Steve. And yes, lock the 'verter in 3rd (with HP Tuners).

I wouldnt trust Comp 105 springs though...I have heard of 2 people that used them and they broke.

[ssms5411]

Re: How much should I push it to?

Trust me, he knows all this ;) lol

Im excited to see the numbers Steve. And yes, lock the 'verter in 3rd (with HP Tuners).

I wouldnt trust Comp 105 springs though...I have heard of 2 people that used them and they broke.

I have never messed with the VCM controls in HP, so do I leave the car in overdrive until I reach 3rd then use HP Tuners?

I had bought the 105lb springs used and when I heard of them breaking I emailed Comp and they had me send the springs to them with no charge to check them. I guess they were bad because they sent me a new set with no charge or shipping. They said I shouldn't have any problems with the ones they sent me. Chris Mayes is the person that took care of it for me, I thought that was great customer service on Comp's part. So I'm not to worried about the springs.

[bigbrian442]

Re: How much should I push it to?

You can leave the car in D3 and use the VCM controls to lock it in 3rd gear and lock the converter. That should keep it from downshifting when you go WOT.

[ssms5411]

Re: How much should I push it to?

Sounds good thanks.

[97rs4life]

Re: How much should I push it to?

get a vid of the dyno runs :)

[ssms5411]

Re: How much should I push it to?

get a vid of the dyno runs :)

What, you want to see it when the .071 shot blows the upper intake off.LOL J/K
I'll have to see if I can get someone to go with me, I'm usually in the drivers seat with the laptop watching KR and my wideband. The dyno guy runs the dyno tells me when to punch it at 2000 rpms and looks at his computer and wideband to make sure I'm not running lean. I'm really thinking about doing the spring/pushrods swap first, if I can get like a week where I don't have any medical appts. or any rehab. to go to. Will see though, I think the last 2 weeks in March is open so far, I haven't recieved anything yet.

[97rs4life]

Re: How much should I push it to?

yes I do want to see the .071 shot run :D

[ssms5411]

Re: How much should I push it to?

yes I do want to see the .071 shot run :D

DO you think I would have any issues with the .071 shot, I mean there is always a chance but in your estimation do you think I would be O.K. with my current mods? Or should I do the springs/ pushrods first?

I'll have to take my extra bottle with me, I think that shot alone will only run a couple of shots until I run to low in the 3-4 lb range then it is hard to get my psi to 900psi.

[97rs4life]

Re: How much should I push it to?

.071 jet calcs out to be around 200hp at the wheels, 225hp at the flywheel. As long as you have the fueling for it and the tune is correct and spot on along with minimal to no KR you will be fine. I would definitely run some octane booster in it though when you do that run.

I would take an extra bottle or two and work your shot sizes up carefully. Watch the KR and a/f ratio each time. Any sign of issues shut it down and don't press it further. With tuning all dialed in you can do the 150-200 shot though with your forged pistons, cam and such.

Do you have any headwork at all? I cannot remember

[ssms5411]

Re: How much should I push it to?

I did a little port/polish on the intakes upper/lower and on the heads in there now are stock with stock rockers and springs. The pushrods are the light weight ones from intense, some say they had problems with them breaking. That is why I might do the 105lb springs with the Comp pushrods first. I know I'm tuned for the .055 jet now but my octane table is set at 23 degrees of timing but when I run it with the .055 my scans show 25-26 degrees of timing with zero KR. I don't know where the extra timing is coming from. I think I will have to take about 2 degrees out for the .063 and 4 degrees for the .071 jet. I have 5 gallons of 100 oct. unleaded and 2 bottles of nitrous 1 with 24lbs and the other with 25lbs.

I also have a TB I ported/polished taking out the under part of the maf out and polishing it out. I want to put that in also for more air flow to reduce puddling. So at this point I'm still debating.

[bigbrian442]

Re: How much should I push it to?

Your going to have to tune the MAF after you install it. There are all kinds of "Little timing adders" hidden in the PCM. You might look at the MAX torque timming table as well.

[97rs4life]

Re: How much should I push it to?

yea half shafting an angled tb is going to be tricky to tune, did you modify the brass plate on the back of the MAF post to still work with it?

[ssms5411]

Re: How much should I push it to?

The TB is not in the car, it is something I've been messing with. I didn't mess with brass plate on the back that has a screw in it. I cut right under it, so the maf would still read as normal. I thought that was the correct way to do it. Is that correct?