I am up to page 146. Some really great info. Along the way, several times dyno-ing just the headers has been discussed, but I have yet to see results.

Does anyone know if this was ever done? I ask because my car is a 2006 with twin cats. With respect to increasing power it appears ecu mapping is number 1 and cats number 2.

I have filters, cats, and x pipe on the way. I plan to swap the muffler for the loss of weight. I have not selected a tuner yet.

I have seen some really good pictures of the manifolds and I question how much the equal length 4 to 1 actually contributes. After seeing the youtube of bashing headers on a big block with virtually know change in output, I cannot help but compare the stock 06 manifold to the gorgeous headers, but not from the standpoint of beauty.

It would be great to have empirical data on the headers. That I can't find it, makes me wonder. Can some one point me?

The intake discussion was very good - to the contributors - thank you.

chr

 

Hi-I added the Velocity AP custom headers and LW Flywheel/dual plate clutch at the same time a few months back and did dynos following. I had last done a dyno following addition of power pack upgrade, 200 cell cats and exhaust which was 3 years or so prior so I can help with a directionally correct comparison but by no means was it directly before then after like when I had the cats done.

I will tell you the CAT's showed the biggest gain for me but I feel there is a point of diminishing return when freeing up exhaust flow. I wanted to do the headers since my buddy and I had already spent like 8 hrs getting the clutch out and the headers were only another 2 hours of effort.

I will post the gains once back from New Zealand.

BTW-I love the LW flywheel and clutch....car breaks loose on 1 and 2nd and lights up traction control into third now....Also-they did a custom tune for me (I rented out dyno and paid Velocity a fee) as no car had the same mods yet. Your car once complete will be very similar....I have prep and post of just the tune. It was a good gain and on top of everything else (including power pack which is mostly a tune).

 

Detomaso - Thanks for the insight. I have spent hours going page by page thru the development of the cars. I am back to page 213. It has been very interesting. I think you are correct on diminishing returns for the exhaust. I purchased the cats and x pipe from Fabspeed. Their posted numbers were quite good and without a tune.

I have changed my mind on the headers. I really like the idea of lightning the muffler. By adding the header and x pipe it seems I can expect it to be quieter. This would benefit me as I could then swap the heavier OEM muffler for a sport muffler and hopefully not be over the top sound wise.

I am still unsure on the tuner. I have contacted Eurocharge twice with no return phone call. I was interested to see a VAP post with plots of all 4 of their tunes. V3 looks pretty good for the hardware I want to install i.e full exhaust from the heads back. It certainly is convenient having the tuner. This is the system we use on my Cobra so I am comfortable with it.

It seems 40 bhp is achievable above 4000 rpm and up 20 ftlb below though it touches the stock curve along the way. Things take off above 4k which is fine for me.

I've driven the car a few times now and the off idle throttle response has to be corrected. I was wearing Wellingtons today and the pedal layout suits me fine for heel and toe. If it could be rev matched it would be hell of fun.The clutch is on my radar.

The discussion with Mike from Bamford Rose (some years back) on tuning was very good. His position was spot on from an OEM perspective. Tuners have been using the safety margin for along time now. It's all risk management and mistakes do happen. More than one Cobra has been destroyed running an over aggressive tune.

Beautiful cars here -

almost forgot - never have found a dyno of just the headers - been at it for days

x-chr

 

Can't help with the header power info (although I do need to get my car dyno'd after I replace my clutch), but the overall difference between 4.3L cars can be huge. There's a small difference between a standard 380-hp car and a 400-hp one with the Aston Martin Power Pack. But there's a huge difference going from either of those to one with exhaust, tune, and weight reduction. It's an entirely different car.

 

I only have a butt dyno but my 4.3L car with K&N filters, VAP headers, VAP tune, VAP LW flywheel & dual-disc clutch, RSC 200-cell cats, and RSC sport muffler feels MUCH faster than stock. Plenty fast. It also sounds like the Vantages that race in the Pirelli/Continental road race series.

 

I have an observation on the filters. I see some have punched holes in their air boxes. I am wondering if anyone has eliminated the boxes entirely and just run open filters. There is a company in the UK that sells such a kit. I can't seem to find them right now, but I do question the boxes. I am sure Aston wanted to keep the intake noise to a minimum and it seems the intake tract to the filters is restricted otherwise why would they add flaps. We've not pulled the boxes yet, but plan to take a look at this while we are in there. The kit I saw used some adapters and brackets to solidly mount the filters.

We run a similar system on the Mustang. It is boxed by the engine plate and surrogate fencing. I am not concerned with water .

Anyone running it?

 

A lot of AM's race cars run with open filters like that. Main concern for street cars is intake noise and protecting the filters (especially from water). If you aren't concerned with that, you'll be mostly fine.
You'll definitely want something to fix the filters to the MAF tubes - the airboxes help keep the filters pressed in place. Removing the boxes would also reduce the secure fitting of the filters in place and you'll risk them falling off as the car deals with the normal vibration/shaking/etc of driving.
Only other concern I'd have is the filters might be working extra hard to clean intake air. The factory setup has an inlet at the grille, which *might* be more clean than you'll get when you eliminate the airboxes.

 

Aston Martin Racing did an engine dyno test on our headers and although I'm not permitted to post it here, I can tell you that there's a decent gain in top end, however the gains are nearly double in the mid-RPM range. Which for the road is actually a lot more useful. We had been interested for some time because we knew the top end gains weren't colossal but that anecdotally everyone said they felt a sizeable increase in performance. I think the mid-range gains are really what is being noticed the most, that extra torque at 4000RPM versus the addition of another 8 or 9 HP at the top end.

 

Stu-Do you know mods the AM Racing V8V had on it pre and post headers when tested?

 

It was a standard GT4 Race Engine. Tested back to back with the headers as the sole variable. Was just over 2% gain at the top end, and more than double that in the mid-range. So on a 400HP car that should give around 8-9BHP up top, and more than double that at say, 4000RPM.

Which confirms the anecdotal feedback we keep getting that the headers make a noticeable difference.

 

Ok so it would have had race cats/cat deletes included in both as well then?

 

Yes, both before & after had VelocityAP FIA homologated race cats, as we supply to AMR for the GT4 Cars.

 

Stock is around 200 bhp @ 4000 rpm - 10%?

x-chr

 

I have made all those tested there several years. I can repost my results.

 

I'm trying to develop an intake system by modifying existing systems on the market. This is better than the system on your pic.
Everything will be finished early next week. I can post any such changes if you wish.