Sounds good to me. You're gonna run 2 wastegate in conjunction with the 2 turbos? I'm going with 2 smaller turbos, internally wastegated, to simplify the piping.

 

Unfortunatly neither Chris or Marcus ever get on the forum anymore. Marcus sold his race car a year or two ago and moved to Mustangs. I think Chris just got tired of people wanting him to write a scientific explanation before they would accept his advice. So sad

I'm still trying to figure out how in the hell Marcus got 28" long twin runners. He must have mounted them up higher than the engine and poked them through the hood haha.

When you make the manifold I'd use a least 12" long runners, run 2 wg's and make the turbos and wg's all the same length from the engine ports.

Your probably going to have a hard time fitting all of this in the car. It would be sooooo much easier with internally wastegated turbos......but I dont know if any of them make the kind of power your after.

Stephen

 

The I/C core wasnt the problem on his setup.. Just all the bends.. LOTS of them.


But the core was an HKS for the 2nd gen RX7.

 

you're in a catch-22, marcel. to feed those turbos you need big ports, but if you have big ports you can easily spool a large single. so you don't really need twins.

but if you are going twins, those compressors are a bit too big.

 

The exhaust porting is quite large so I dont think there would be a problem spooling two turbos and I already have a pair of 35mm wastegates . My alternative plan is to stay single but change to a GT42RS , I know its a big turbo and its a bb , but I'm not sure how well it will respond , this is why I am thinking of going with twins , I want a little more power down in the RPM range and still have enough capacity for high peak power . From my experiences with the large TA45/51 , in the lower and mid RPM' range there was quite a bit of torque (cost be gearbox and clutch and a diff) , but as we know you can never have too much torque.

 

Marcel you have PM

 

You have one too.

 

What about me? Do I get one

But really, why not share with us all Peter? I have a feeling what you have to say might intrest a few of us.

 

Seeing that the GTR turbos are just too EXPENSIVE for my budget , I am thinking about using something like a pair of GT35 's with T3 turbines in .63 housings ??, what yall think ?.

 

Marcell- What is your goal with the engine in rwhp/spool time/cost??? That would be the deciding factor. The only reason I really see to go to twins is the packaging for a large compressor. If you can achieve your HP goals with a single(that will fit) why not keep the ease of installation. For example: On my current project we were going to go with a large frame T6 88mm y2k. The housing would more than likely run into fitment issues, not to mention the immense 4-5" DP that would need to fit as well. Now, instead of this we found we could package a twin system that would flow the same( actually a little more) and would be easier to package.

I believe you mentioned you were running a t70 ptrim??? I thought you were running a t51 ~76mm 1.32??? Were you not happy with the t51? What happened?

****, if you want more power,torque, reliability........COME TO THE DARKSIDE

1000+ rwhp is waiting..........uh......come to think about it.......torque/reliability are waiting too....hehehe

 

My goal is to have COPIOUS AMMOUNTS of horse power , the sky is the limit !!. I have been running a LARGE TA51/45 with my last half bridged motor , it worked well , lots of power and torque below 5000RPM's . I an presently redoing my set up and I am changing my turbo , my choices are between a BB GT42(RS) or twins . I want the hp but I wouldn't mind improved boost response , this is why I am looking at the twins , I dont want to go over 2K for the turbo , I am not sure what the response of the GT42 would be at the lower rpm's . I know its easier to do a single setup but I figure the twins might be worth it.

 

How much are you expecting to gain with your turbo swap?

What did you used to dyno at with the T51?

Is this a street/track car?

 

I am expecting (hope for) 550+ BHP , I never got around to dynoing her . Everytime I decided to , something would break and something else would begin F@#$king around , it went from my diff to my tranny to boost creep issues to inadequate fuel etc, etc . I eventuall popped two seals on my front rotor after screwing around with my E6's trim **** (a/f ratio) , damaging the front housing and front iron . The opportunity presented itself for me to go semipp , so here I am !

 

Im suprised that you would need to change turbos to get your goal, what is the comp. inducer on the T51? 76mm? Q/R? 1.32?

Just wondering, if that turbo could get you to your goal, why not put the extra $2000 into a nice intake mani, suspension work, etc,etc. 550rwhp has been done plenty of times with turbos around that t51 size. The turbo we are using to build the rotary car in my sig. is using a custom 76mm comp, .96 ptrim. We are looking for basically the same #s as you want(550-600rwhp). Dont let people fool you into thinking a p trim wont support 600+. We just choose the p trim b/c it lets the boost come on a little more gradual than the Q, giving a better chance to hook/and not break driveline parts as easily with the shock. The GTQ wasnt out yet, and I would think it would be a perfect way to go. Have you read up on a the 76GTQ/S?( I think that was right). Bad *** turbo. Alot of supra/V8 guys are using putting out ~900 before they top out.

I could be wrong, as I am by no means a rotary or turbo or automotive expert at all. But, IF you were to go twins I think that a T4 series would be alright, just abit smaller compressors than what you were planning. Maybe something in the 54mm range. You have ALOT of options to choose from in turbos to get 550.

What kind of % of track and street would it see???

And you know what Im going to say.....If you want more hp,more tq, more reliability....THERE IS ALWAYS THE DARKSIDE!!!!!

 

I Dont do the DARKSIDE !!! , hehe . My turbo has a TV76 compressor wheel , which is a bit larger than a T76. The street / strip use would be like a 80/20 split , this is why I am thinking about faster boost response. I am not putting out an additional $2000 , the turbo has been sold (down payment made already) , so I just have to put an additional $300 to make the total. I am still not fully decided on the twins yet , if it proves too elusive (getting right turbos , making manifold etc. ) , I may just buy a new GT42RS and be done with it.

 

Specs on the turbo here :https://www.rx7club.com/showthread.php?t=368224

 

That TV series is straight from the diesel trucks. Big, heavy wheels for sure. That GT42 may be the way to go. Like I said, if you went with twins you could get a way with it fairly cheaply. You still have those twin Wgs right? I would just look into a pair of ~54mm and I think you would be good, standard Garrets. Again, I get my info off of Davinci Motorworks, and a few outlaw/pro mod/super street guys. Maybe give Davinci a call, they are much better at the airflow/turbo sizing calculations than I am. Ask for Mark/ Ron and let them know JT reffered you.

 

Thanks for all your sugestions and help , I will let you know what I eventually decide to do.