Help me choose which BEGi DP
 

Nissan T25
Enthuza 2.5 exhaust

Goal: ~200 whp

I bought the BEGi-S downpipe when the prices were going to increase (much to my dismay, they are on sale now for cheaper than before :vash:), however yesterday I bought a BEGi SS divorced downpipe as well. Now I have 2 DPs.

Can the T25 w/ BEGi-S DP handle 200whp or is the DP just too poor of a design? Or should I go w/ the divorced DP? Will it really make that much of a difference? I've never seen dyno runs that compare non-divorced to divorced DPs.

Or should I just get a welder to modify the BEGi-S to a bellmouth?

I didn't realize this at the time of purchase, but the upper part of the "S" DP is only 2 1/8"! I was told by BEGi that it was 2.5" DP when I bought it. I assumed that was the entire DP piping size. It only swages to 2.5" at the outlet. Is this how all BEGi DPs are (super small DP inlets)?

If you are hurting for money and want to sell one or the other, you'll obviously get more $ for the nicer divorced gas one and the BEGI-S DP will probably do all right for you.
That said, if I had both sitting in front of me, I would absolutely choose to use the nicer divorced gas one. The design in many ways (not just that the wastegate is divorced) is better. Sell the S DP to someone piecing together a budget kit.

-Ryan

At 200whp it doesnt matter, use the cheaper S pipe.

I think the S pipe is such a horrible design (reminds me of the original greddy) that you would be wise to go with the divorced pipe. No matter what your power goals are, spool is still important.

Honestly if it were me I'd sell both BEGI parts and get FM's DP. I think it is a better design in a lot of ways. If I could do over I would have gone FM on my DP.

All downpipes leave the turbo between 2" and 2 1/4". Then progressively swage up. Either to 2.5", 2.75" or 3".

The BEGi-S downpipe is capable of handling up to 220 whp (that we have actually dyno'd). I would not worry about it. You will probably get more money for the SG DP than the BEGI-S one as we have changed the design.
Stephanie

Better design? Not even close.
Easier to install? Totally.
Stephanie

Bias much?

Let the public decide.

I prefer BEGI's design.

Shut the fuck up.

How 'bout you shut the fuck up punk bitch unless you have something constructive to add to the conversation. This is not the Begi site, it's the Miata site.

lol Feel the love in here.

Like almost every other owner here that has felt boost in their car, you're going to eventually want more, so then you're going to want the better DP. The SG DP is a pain in the arse to install, but it's worth it, so I'd say do it once and be done with it.
So I 2nd the suggestion of selling the S to someone building a budget build. I just so happen to have a friend looking for one if you decide to go that route.

Its not your fault.

http://farm4.static.flickr.com/3101/...7911d2.jpg?v=0

The DP can be a bitch to install, but its not that bad. You just need patience and man hands.

I also vote for using the SGDP. :bigtu:

edited: I must not be mean I must not be mean I must not be mean

Do not ever type to my bitch like that again. If you have a problem with him, it goes through me, and I'm fairly certain that unless you want my little faggy dog to make a collar out of your spleen, then you can stfu and never bring your horse-shit disrespect and ------ry to this forum again.

my SG DP was pretty easy to install...and most of you whiney ------s in here need to go to the gym and pick up some iron for the first time in your pathetic lives.

Can't we share him? He seems to be more than willing to be a receptacle for just about anyone.

Cast upper section, mandrel bent lower halves. Zero welds to fail. O2 sensor bung in a useable place? Fits properly? So where exactly does the design fall short?

We know that there is at least one ~400whp-ish stroker running about using that DP, so it can make big numbers. The dyno charts showed pretty decent spool.

Better on paper doesn't mean better in reality. If BEGI is going to claim what they have is superior, prove it. Otherwise it is just marketing BS.

I still stand behind my idea to sell both BEGI pieces and purchase the FM DP. The user is looking for modest numbers, so any edge BEGI has (imagined or otherwise) is moot. So what's left? Fit. Ease of install. Durability.

Why?

I'm sure from where you stand you are pretty confident in that statement. What is better about the design?

Better design or not isn't going to matter to you when your ill-fitting Begi piece makes your exhaust bang around the underbody like a mofo. I'd go with something that was a guaranteed to fit if I was going to order a piece again or I'd get one made locally/learn how to weld and do it myself.

Is a Nissan T25 even capable of 200whp? I know I wasn't exactly expecting that much with mine.

I have heard of people getting 250whp on a SR20DET w/ the stock turbo, so I would think we could get at least 200whp with a little less displacement. I am hoping for 200-225 out of mine.

SamNavy made ~200whp. I think he was also using Borla duals as the exhaust, so it could only have gone up if he changed out the exhaust.

Go with the Begi S.

Save your money, get something going, and by the time you need more power, you will already have everything. It will be just that much simpler to pull the trigger because you know you didnt pay a lot for something not here nor there that isnt letting you justify another upgrade.

My :2cents:

Besides man, think about it. The rest of your build is cheap, why even bother with a better DP. Trust me the Begi S is plenty. Either go all the way with every part, or none of the way.

There are many things that are superior in design. And you did say design. What you refer to above is constriction. But let's break both down...

~Cast upper section - weights more than stainless. The entire SG SP weights 12 lbs. It is highly unlikely that the FM casting plus the lower section weights less than that. Our cast upper section used to weigh 11 lbs.

This part also contains the "Separated gases" design. Are you telling me that the 3" of separation is superior to our 20"+ length? You can't. Period. In all reality, our worst downpipe - the latest BEGI-S - is still superior to the FM design.And cheaper to boot.

~Mandrel bent lower halves - something to be said for that. However, your statement of zero welds is false. I know of at least two welds, possible more, that HAVE to exist on that pipe. When FM was first designing this pipe, Bill made a point of saying that it cut the existing number of welds (which was 7 at the time) in half. But lets be honest here - cracks in welds usually occur at the flange. Their flange is welded on, so it ours. I have never seen a downpipe crack in the middle, only at the flanges. They have the same opportunity to crack as ours. Besides, we use mandrel bent tubes also. Just a few more than they do.

~O2 sensor bung in a usable place - I would have totally agreed with a year ago. But, we seem to have all the bugs worked out, or we are getting closer at least. Both with the stock sensor and WB O2.

~Fits properly - no one can guarantee fit of a pipe. There are different cross members on certain year cars. People have modified existing exhaust systems. Too much room for error. And most people are not the original owners, so who knows what has been done. I have seen some strange stuff. Sure, we get downpipes that bolt right up here, and we get some where a cross brace has to be modified. But I bet if you start asking, people with FM turbo kits had to have things welded locally etc. I know I have read as much on the m.net website posts. So this one is a toss up.

~Ease of install - No doubt, FM has us beat there. Our downpipe will be harder to install. But 99% of people say it was worth it.

~Durability - I'd have to say this is a toss up to. I have had one reported crack in a SG downpipe in 4 years. A casting can crack, it is a little less likely. But it all depends on metal alloys and the casting processes used.

My dyno charts show equally decent spool, and our pipe has also been used on several high HP applications. They only way to get a correct comparison is on the same car, different downpipes back to back. I have already volunteered to test it, and pay for the expense to do so. Bring me a car with an FM pipe. We can test it, the owner can install the new one, and if mine is worse, the owner can have the pipe for free. Plus they just got free dyno runs.

Warranties, I am sure are the same. Our pipe does cost $66 more than the FM pieces. So in the end, the owner will have to decide if it is worth it for them. But I do stand behind my statement that the design is superior, and installation of the FM piece is "totally" easier to install. If than for nothing else, the vent tube is about 5 times longer than the FM piece.
Stephanie

^ Steph, can I just be really honest and say youre totally hot when youre angry.

The begi down pipe can be a pain in the you know what to install... At least from my experience.... It was the only part of my kit that I didnt care for.

If corky gets rid of that anchor bolt and prewelds the gosh dam thing, it might not be so bad and possibly even PnP. I would pay for the extra shipping if thats what it takes, its cheaper than finding a welder. However with that being said I would still choose a BEGI kit over FM if i had to do it again.

As far as numbers I really wish someone would dyno them both on the same car and tune and put down some numbers, I really dont think that 200-220 at the wheels is going to make much of a difference on any of the three. So keep the one that is stainless :)

I'm with you on all of this. My dp was pretty difficult to install, but works after following the instructions closely. I have not yet, however, been able to get rid of a nasty, stupid sounding exhaust leak at the slip joint.

For the slip-joint leak, assuming the bolt is tight, try some high-temp silicone.

FWIW my stainless BEGI-S pipe fit perfectly on the first try, and the stock and WBO2 bungs were correctly located. I just picked up my BEGI SGDP (stainless) today and it is beautiful, just like the S4 manifold. I'll be installing both this weekend.

Edit: Got the stuff installed today. The DP fit just fine.

My bad, 4 welds, not zero. I wasn't thinking of the welds on the flanges and o2 bungs.

+1 i've yet to see any evidence of superiority of a separated gas downpipe

What if someone made a 3" bellmouthed downpipe? (3" starting at the turbo)

If they used that 3" bellmouthed downpipe with a measly 2554 I bet they could make 233hp/235ft-lbs with a decent tune one a very old ass 1.8 approaching 300k miles.

https://www.miataturbo.net/forum/t33260/

This guy's car made 210 hp / 198 ft. lbs. while my very similar car made 213 hp and 205 ft. lb. .... so big deal you say, I gained 3 top-end hp and 7 ft. lbs. ... but consider than other guy had a boost controller and a big IC, whereas my car ran wastegate pressure and a puny IC ... yet my car still made more power. I attribute that to the SGDP (thank you TurboTim / Shore Motorsports).

The next time I get to a dyno, I might take one pull at 11 psi (vs. 15 that I run now) just for comparison sake now that my car has MS / boost controller / big IC.

What boost was he running, Im making around 210-213 ant 11psi.... If you are doing 213 at 15 psi that doesn't seem very good.

Well I guess if you are still running the stock MSM turbo maybe?

I think that you would have to consider cars with the same turbo setup, size and boost pressure. 5-8 hp difference I probably would not even pay attention to because of the differences in motor tolerences tunes ect.

While it would be easier to install, but the design is lacking. It will create too much turbulence, therefore impeding the flow of gases. There is also the problem of too large of an opening off of the turbo. There is no reason for a 2" hole to have a 3" opening.
Stephanie

I was not counting O2 bungs. There are welds at the flanges though. Last time we looked into it - it was not possible to make that many tight radius bends on one bending machine, on one tube.
Stephanie

I would use a rubber mallet and make the opening smaller. Just be gentle. The metal should expand and seal itself.
Stephanie

Evan is using the stock MSM turbo.

Also I was only running 10.5+creepage that day on stock 6500 redline.

So, despite no boost controller + stock turbo (pre-porting) + 6500 redline + puny intercooler, my car STILL made more power than the other guy. :) That's all SGDP.

And the Absurdflow 3" exhaust.

OK thats a better comparison... I though you were running 15psi and he was like 10.