bmwtye

Thanks for this info. So with cams, this completely new manifold, and all other associated parts, sounds like there is the possibility of getting the 3.6 over 400 rwhp

RSRanger

I am coming in late here to the discussion but I have a bit of experience with my 997.1RS engine build.
My build went thru the initial phase using the 3.6 intake manifold, then going with the 4.0 intake manifold (was really hard to get back then due to the recall).
My question is, are you guys using the 4.0 injectors? As it was explained to me these injectors do not necessarily deliver more fuel but they have a better atomizing pattern than the 3.6/3.8 injectors.

Ranger

Jamie@dundonmotorsports

Hi Ranger

For the bigger engine builds we'll look at it, for the smaller bolt on builds is likely overkill.

Spyerx

On a tuned 3.6 they need breathing at top end that is where the 3.8 manifold will help. You can see it in the dyno graphs, the start to flatline HP at 7500 or so. 40 will be overkill on a 3.6. You will need the full setup intake runners and center sections.

Bmwtye, on cobbs dyno in SoCal mine did 408 rwhp on their stage 2 100 octane tune totally stock motor with cup exhaust system. 396 rwhp on 91 ca **** gas.

Charles@dundonmotorsports

The side 3.6/3.8 hybrid plenums we are making will work with the stock 3.6 center plenum section


I always love the dyno runs of those who never get a baseline. It doesn't tell you much of anything. Makes me want to go to the other dyno jet in town just so I can show how a stock 3.8RS with all my parts makes over 500whp.

Spyerx

Not sure what you're suggesting or if that was directed at me. I don't have a baseline for the headers with stock tune as those were done a long time ago, but I do for the COBB tune before/after (it was done on their dyno in Costa Mesa by Mitch). Are you're saying COBBs tune #'s are full of **** or fabricated? We all know numbers vary from dyno to dyno, but pretty clear what I stated: stock tune with cup headers and side bypass 386 base, 396 tuned for 91ACN, 408 on 100.

But I don't think that is what you were saying.

I'm also not saying your headers don't make power. They look like a good design and I'm sure they do well. It's well known on these cars that pulling the cats and improving the collector design/equal length is good for a big bump. Center stock muffler works well too and doesn't drone.

John Chan

I think Charles is referring to our local shop dyno machine # are very conservative and my stock baseline was 357-360whp. With Cobb 91 stage1&2 with 92, my car did not see much different in peak power gain.
With Charles header with stock or 91 stage2 tune on 92, peak power gain is 20 and mid range about almost 30whp gain. We noticed the 3.6 intake is chocking the engine at peak power.
Anyway, peak power on our local dyno was 380whp with charles header and stock or stage2 Cobb tune, almost same # anyhow. Most likely will read a lot higher in other dyno base on the baseline reading currently at 358whp.
With the baseline reading for the delta gain before and after the mod, the story is very clear and dyno calibration factor between machines is no longer a debatable subject.
The delta gain for the mod in a same day dyno was the # Charles reported. As a customer and engineer, I look at the delta gain # as a lab results without any marketing assumptions build into. Also, I was at dyno with Charles witnessing the process and data, there is no BS with his work.
I had been seeing too many dyno results without a proper baseline comparison for the mod on many cars. A lot of the mod can't pass my butt test
I hope we are living in a state with 93 or 95 gas to make good use of our engine.

Charles@dundonmotorsports

My statement about the power numbers you read into it too much. People are fast to say that their car with just a Cobb tune made 400whp so why buy your stuff that only makes 380whp. I have been having people tell me this for years that my stuff doesn't make power because the number is low but I seem to be one of the only ones out there showing consistency and gains over stock not just bolt on parts and strap down for a number. A single dyno number on a modified car is pointless and dimensionless if there is no base for comparison.

I do not attack other vendors or such as that is not how i do business. I am about promoting my own products and proving why they are better. I do not need to discredit others products. Sometimes I will see a chunk of false information posted which is only meant for missleading consumers into their product but this is not that often.

One thing I don't like is when someone says they got a tune and picked up 10whp and they think it's 10whp across the board, then they put it on the dyno and it makes 2-3whp everywhere and 10whp at redline for 200rpms. So the car will not accelerate at a faster rate of 10whp more except at that one spot.

Another thing is dyno consistency. Everyone will always post one run of each. Usually worst of the stock and best of the best modified or tuned. A lot or most of the time that setup will not consistently show those results over and over. I choose to and will always be open to posting my dyno results with several runs each. If you look at say or 991 gt3 dyno I have several sheets showing 3 stock runs back to back to back with 3 modified tuned runs back to back to back showing that this is consistent and proven reliable and repeatable power gains not just one lucky pull after the car cools down or has the intake manifold iced up. These cars when driven on the track are always hot and heat soaked and run for 20-40 min at a time so why not show gains when hot and that this power is there all the time not just to sell a product.

The more information the better.

Charles@dundonmotorsports

So I figured I would share our PRE full tune results with the 3.8RS. We will start a new thread once full tune is complete and available.

What is shown is

2) runs bone stock 3.8RS
2) runs with our 3.8 Headers and side flap pipes with OEM center, with high flow filter air box
2) runs with the same above except with a 4.0 IM installed

the runs with the header is with a cobb stage 1 installed. I never spent the time to revert back to stock as I didnt have much time. Before when i did not have the air box i checked stock to cobb-1 and it was smoother but no huge gains, so I figured since we are going to full tune this, then no big deal.

40whp over stock @ 7300rpm
40whp over stock at 8400rpm

the difference around 78-7900 is most likely where the 3.8RS is tuned for, as well as this is not a full tune with the 4.0 manifold and air fuel and timing is all over.

The big dip at 6500 is where the resonance flaps change over and thus cause a huge difference in air flow. We can not change this with the cobb, so we have to go with TTFS to tune this out as well as a lot of other things. If you notice before 6500 the 4.0 is starting to make more power, then the flaps change and the dip is there and then the recovery is a little slower for a few RPMS then it out gains. Once we have the full tune this should all be gone and I expect the 4.0IM to make more power than the 3.8IM everywhere expecially from 6000+

AS FAR AS A DISCLAIMER I would not expect the 4.0IM to make power on anyone elses engine unless they have our headers/exhaust on it as well as our airbox. the stock air box restricts before we get to 420whp and it just doesnt want to make more than that no matter what we do. If you have someone elses headers/exhaust on it and install the 4.0IM setup I WOULD NOT expect you to make gains, but most likely you would lose power. Installing the 4.0 IM means you have to install the lower manifolds as well onto the engine so this is a big job for most and will take a while to do engine in the car or some may just want to pull the engine.

We will be selling this as a complete package when ready, most likely.

Charles@dundonmotorsports

deleted, wrong thread