Tune Questions with Blower swap

[PNWSVT]

For those of you who don’t know, I just did a rebuild on my 03 cobra. I was able to retain most parts, I upgraded what was needed, full ARP, Boundry oil pump gears, Canton pan and tray, 8.3:1 CR, comp stage 3 cams, and the newest part is the supercharger.

I went from a 3.4L Whipple to a 2.3 VMP with a 2.8 and a 4# lower. From what I understand this should have me close to 20lbs of boost. I have DSS Forged pistons, new rings, factory rods and polished crank. Again ARP 2000 studs and bolts everywhere i could go.

My AFR before the rebuild was 11.1, What can i anticipate on fire up? is it desperate I get a new tune right away? I know I have to go threw the break in process still but I am trying to weigh the pros and cons of a Dyno tune vs a download off here.

I have heard two different opinions with mainly people saying a dyno tune doesn’t mean anything on the street, its just a snapshot of the most amount of power your vehicle can make, and its expensive vs. a tune and data log ( then tweak tune) data log and repeat.


What are your thoughts? If you guys think the downloaded tune is a better option, which guy on the site has the goods? and SCT Programmer?


Murph

 

[MG0h3]

Yes absolutely have the tune revised immediately. O4sleeper, malcolmv8, and we have one more I cant drum up the name though.

Why so low on the compression?

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[01yellercobra]

If you kept the same injectors and MAF your part throttle should be good. But your WOT is more than likely going to be off.

Remote tuning isn't bad if you have the place to drive it, know how to datalog, and have the time. Dyno tuning is pretty much drop it off and pick it up. Provided there are no issues. I prefer street tuning for part throttle no matter what. It makes for a better tune in the end IMO. The tuner I learned from would get the part throttle dialed in on the dyno. Take care of the WOT on the dyno. Then jump in the passenger seat and have the owner drive around. He made any changes needed to part throttle at that point along with a final check of A/F at WOT.

 

[Curt@injected]

Most good professional tuners are going to tune the car on the dyno and then on the street. It's a combo not just tune it on the dyno and hope it drives good. With most setups an experienced tuner can get them pretty close on the street with a wideband but it's not the safest environment for tuning. A dyno is a tool, it's useful to see if your changes made a difference in power and where. Whether it be spark, fueling, cam timing(clearly this doesn't apply here) etc. It's more difficult to do that on the street.

 

[Soap]

Why so low on the compression?

This.

--Joe

 

[Curt@injected]

Agreed the compression ratio is going to hurt power.

 

[Weather Man]

That compression is better suited to a turbo setup.

 

[PNWSVT]

Yeah I had zero choice in the compression, the pistons are -21cc dss gsx pistons and with the 53 cc heads it just equals out to 8.27:1 so I can’t do anything about it unless I shelled out money for more pistons which I didn’t because I couldn’t and I am not a millionaire.

I have a tune apt next month at the local shop turbotech on Jan 27th and the tuner (well reputable) told me that at that compression ratio with my setup I’ll be golden around 20psi.

 

[PNWSVT]

He also just said to gap my plugs at .25 (tr6)

 

[PNWSVT]

Yes absolutely have the tune revised immediately. O4sleeper, malcolmv8, and we have one more I cant drum up the name though.

Why so low on the compression?

Sent from my SM-G950U using the svtperformance.com mobile app

You guys have a tune?

I’m not sure how it all works anymore, I know I gotta buy a programmer (sct x4 7015) and i realize the spark plug gap comment made no sense lol I just finished a final in school and went to the bar and a gorgeous woman walked in so I just said what I said lol


Here are my modifications from bottom up

Canton Pan
Canton tray
ARP mains/jacks/rod bolts
Stock rods
DSS GSX pistons -21cc
Ported and polished heads with ARP studs
Comp stage 3 cams with springs and retainers
Weapon x coils
FORE fuel system -10 feed -6 return PTFE braided
65cc injectors (same as before)
VMP GT500 blower with a giant damn throttle body lol 2.8 upper 4# lower
EGR Delete
Snow performance water/meth kit
Tr6 plugs @.25
Full lentgth headers, cat less , x pipe

26 spline input shaft
Centerforce DYAD-DS clutch kit
Ken Brown full subframe system
Stage 2 halfshafts

I’m sure I’m missing something but lets get this bad boy a tune!

 

[MG0h3]

You really cant steal a tune from someone else and expect it to work correctly. Like mentioned you could get by if you have the same injectors and maf but stay out of boost.

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[blownstang4.6]

Sucks that you couldn't swap out the pistons for higher compression. Low compression is a big power killer. 93 tune on meth or doing E85 too? No WOT if you're not changing the tune right away.

 

[PNWSVT]

Yeah well it is what it is, rumor has it that an E85 station is going in a few blocks from my house , which is huge since there’s literally 3 in the state. So I made sure my fuel system was prepped for it in the future.

 

[PNWSVT]

You really cant steal a tune from someone else and expect it to work correctly. Like mentioned you could get by if you have the same injectors and maf but stay out of boost.

Sent from my SM-G950U using the svtperformance.com mobile app

Yeah I’m tracking that, but I have done tunes on a few diesels where Tjeu would build a tune based off the parameters I provide and then I download the new tune into the ecu

 

[PNWSVT]

also before the fuel system upgrade and blower swap it made a best of
622hp @ 7200 rpm
515tq @ 4850rpm