C5XTASY

Title pretty well says it. I have a heads, cam, intake, injectors, longtubes, Blackwing, GHL catback, screenless MAF, Yank SS3200, etc., car with a full dyno tune. I just picked up a Shaner ported and polished throttle body. Do I need any additional tuning, or should I be all right just mounting it and driving with it. Thanks for any input.
Ed

chriswtx

No, you should be fine. Install it and drive..

C5XTASY

I thought I might have to have things adjusted to allow for the greater air flow at lesser throttle openings. Will A/F ratios remain okay?
Ed

'VETTE PHASE

When I did my throttle body, my tuner said it gives it about a 3% lean condition when done correctly. I'm not sure if the computer can compensate for this or not, but he redid the tune on mine and I could tell a difference between with the tune and without. I had driven the car for only about 30 miles with the throttle body done before the tune, so that may not have been enough time for the computer to make its changes. Just my experience.
Your mods are more extensive than mine, so that may make a difference. I have longtubes, x-pipe, Corsa pros, Blackwing, ported throttle body, with a street tune not a dyno tune.

chriswtx

With you mods and tune the throttlebody wont make a difference in the AFR. The MAF will see the greater airflow and put you in the correct cell for the airflow...

vettenuts

Depending on how deep Mark had to go due to voids, your startup RPM may be high. You may need to adjust the startup parameters.

C5XTASY

I guess the only thing to do is to stick it on and give it a try. I was concerned about possibly running lean with it. I'll check with my tuner, DRM motorsports, also, and see what they have to say. Interesting...
Ed

C5XTASY

This is interesting to me. By 3% lean, do you mean 3% leaner than current A/F ratio? For example: If my current A/F was 12.5 would it move it to 12.88?
Ed

'VETTE PHASE

This is what I assumed he was saying, as that was the data that he was looking at when he said it. He basically said, in conversation, that a good port job would lean you out about 3% and that I had not reached that yet. He then asked if I done the backside and I said I had not. I had also not filled in the rectangle port and JB welded in a piece of tubing, smoothing out that whole area. Once I did that and did a little more porting, I returned it to him, he then said that it was where it needed to be.
I will call him tomorrow and find out for sure so I don't post anything misleading.

vettenuts

You could also just call Mark and talk to him, he is a very nice guy and fun to talk to

C5XTASY

Sounds great! Thanks...
Ed

'VETTE PHASE

Yea, I know, it's not tomorrow, but better late than never. I finally talked to him yesterday and he said that it was 3% on the A/F ratio.

C5XTASY

So, then it would move whatever A/F ratio a person had 3% leaner, as mentioned earlier in the example of a 12.5 A/F moving to 12.88? I wonder if that's enough to make any discernable difference in performance or potential harm to the motor?
Ed

'VETTE PHASE

Correct.
It definately mades a difference on mine. I could tell a difference immediately, just driving down my driveway (it's about 1/4 mile long), on the low end throttle response.
I doubt there is any danger of doing any harm to the motor, because my tuner told me to drive it for a few days and then bring it to him and he would re-do my tune. The low end throttle response was noticeably better, but the top end felt a little soft. The re-tune took care of that.

C5XTASY

Out of curiosity, what sort of mods do you have and what kind of tune did you have prior to the throttle body install? Mark told me this, in an email last year, when I was thinking about installing one of his throttle bodies:
"No retune is needed as long as you have a good tune already. The ECM will relearn in a couple of days of driving. I have seen some very big gains with a retune on a few cars that have had poor tunes to start with though. 1 car made 27 and another made 21 more HP by getting a retune. This is very rare and if your tune is good, a retune might only get you a couple of HP."
The reason I started this thread was to see if people had experienced significant improvement when installing a ported throttle body, without a tune. I have a full dyno tune in the car now, and with mymods, the car is very strong. I am waiting on the arrival of the piece and am anxious to install it. I will have to check with Doug Rippie and see if it would be worth a retune, considering my exisiting state of tune. I believe the improved throttle response will be there, tune or not, as porting gives an effectively greater throttle opening at any given throttle position.
Ed

'VETTE PHASE

Prior to the ported throttle body, I had a Magnaflow x-pipe, Corsa Pace Cars, coolant bypass, 172 degree thermostat, Z06 airbox, and an LS1-edit street tune. This was the cars first tune and it was mainly to remove the skip shift and to turn the temps down on the fans, and secondly, to tie the few mods I had done, together.
He told me about porting the throttle body, so I came home, got on Corvetteforum.com and learned how to port it. Like I said, it was not so much a big horsepower gain, as it was better throttle response on the bottom, just off of idle. This was with just 15 miles since getting the first tune.
After a few days I took it back to him to get his approval or disapproval on the port job. He showed me a few things extra to do on the throttle body, so I did a little more work on it, including taking the lip out of the backside and filling in the big hole for the valve cover vent (replacing it with a piece of tubing cut at the same angle as the throttle body). On the next trip, with about 30 miles since the first tune, I bought a used Blackwing from him while I was at his shop and swapped the Z06 airbox out, this was when he did the second tune, which I could feel on the top end. Some of this was probably from the Blackwing, but there was definately better throttle response with just the throttle body.
Now, with the mods you have, especially the H/C, you may not feel a difference, since, I would say, your throttle response is outrageous anyway.
Not to change the subject, but I am shopping for H/C right now. What did you use and what gains did you get from it? After this, I will be getting a dyno tune.