This weekend was the "Chin Motor sports" track event at Barber Motor Sports Park, in Alabama. We went there to do a side by side comparison on both the JWT 700BB turbo and hybrid 850BB turbos. We did the comparison on the following things, Spool up time, power, and power delivery. My car ran at waste gate springs (12psi@480 ponies), and Sharif's car ran (don’t quote me on this)470 @ 13.5 low boost.
On this particular track our lowest gear was 3rd and highest 5th, just to give you guys and idea of the lowest and highest gear reached.

Eagletanggreen Review

After running a whole 30min session with both cars, I was surprise to say that I was very impressed with the power delivery of the 850's. During mid corner throttle I found that I could come on the gas a little bit more confident with the 850 than the 700's. It seemed that you had to wait just a little bit to point and shoot with the 700's, as with the 850 you could get on the gas a bit earlier. I never felt like I had to wait to point and shoot the car with the 850's the power was so linier, and not peaky. Spool up time on both turbos was not noticeable, I was able to get on the gas with both set ups, and build boost. I had more than enough boost and power blasting out of the turns (to much power). On both setups I found my self holding back a bit as I accelerated out of some high speed turns, both cars had more than enough power. However the 850BB felt a bit much stronger up top, feeling stronger as the rpm reached the 7.5K redline. The 700's felt just as strong in the initial burst, and pulling hard to redline, but not as much as the 850's.

My conclusion
From a regular guy just like all of you

Both turbo kits are outstanding; both kits come with Garrett state of the art ball bearing turbos. The 850 will make more power than the 700 at any boost levels, and have allot of potential to make stupid power on a motor with big head ect... The 700's are like a Greddy kit with better turbos, and a more linier power band (perfect for road course) very controllable not like a punch you in the face power delivery of a Greddy kit (on a built motor).

If you’re looking for a kit to make stupid power, take to the drag strip and run low to mid 11's on "low" boost, and then next weekend take it to the road course and get a good confident power delivery with a nasty top end that pulls for ever then get the 850's

If you don’t care what you run in the 1/4, and want that early mid power for your everyday driving, and awesome road course power, I say get the 700's.

Overall I love my 850 and would not trade them for some 700's. They are a beast for drag racing, super easy to drive hard on the road course and pull harder than the 700's up top and make more power. However I just have to give up a little bit of mid range in comparison to the 700's. Heck how’s 701hp with no major headwork.

Here are some pics to hold you guys off till we get the video together.

This write up was for all you guys here in the Z comunity that is thinking of buying or upgrading your turbos, and arent really sure what way to go.

Special Thanks Sam @ GTM for the quick turn around on my ecu, Chris from FP our pit crew boss, Jose Escobar for the suspension recomendation (worked like a charm), Sandy for hooking me up at Hotel counter, Chris once again for building such a beast, Sharif for turning the boost controller off (for my own good )

Car getting corner balenced








Loaded up ready to go!




Track side!

 

Reserved for Sharif's review and video

Thanks guys...had a really fun time, and both cars ran strong and cool!

Sorry I didnt post sooner, but I seem to have caught the flu, and I am feeling pretty crappy today. Couldnt have picked a worse week to get sick.

Anyways, my times with the 700bb were two seconds faster than the older Greddy setup, and still encountered some light traffic. With the Greddy, I ran a 1:44 with zero traffic, and now with the new setup 1:42. Power with my 700bb kit was 440whp at 10psi, and Greddy had about 450whp at 9psi, so very close in terms of peak power. The 700bb kit, and the 850bb both had spool characteristics and transitional response, that seems much better suited for the circuit course. I found that I could apply power much sooner in the corner. With the small exhaust housing on the Greddy, high RPM light throttle angles, would cause an immediate 12+psi in a second, and tended to upset the chassis.

Then I switched, and drove Eagle's car with the 850bb's, and wow is all I can say. The top end thrust was impressive, and it just continued to pull strongly to redline. Becuase he was running smaller than ideal NT-01's, and street camber settings, the car was a handful to drive fast, but I did enjoy the power delivery, and didnt feel the larger turbocharger was a handicap...at least at this track. If a track required 2nd gear, then I think i would feel differently.

I am still feverish, so I applogize if my post is thrown together...i will post more details later.

 

nice comparison. I think If I ever decide to go twins I"m gonna hit up the 700bb jwt kit

 

That my friend is an excellent choice!

 

Interesting... thanks for the write up

 

Nice write up! Thats cool you were able to do a side by side comparison.

 

very nice write up making me have 2nd thoughts about getting the greddy twins on my tt build. do ya know where i can find specs on the 700bb and the 850bb kits? I looked on JWT's website they didnt have any.

 

Thanks!

You are the only other guy I know that have these Turbos (other tha you know who )

Whats your opinion? I know you had the 700's before.

 

The 700's are basically GT28 where the 850's are GT28 with a GT30 exhaust housing. I may be wrong but I am pretty sure.

 

Steve Mitchell has some too. I have never had the 700s, I went straight from the good 'ol 530s to the 850d . You can imagine the difference. Making that jump though did have a noticeable difference in lag. Other than that the power and pull to redline was STRONG compared to the 530s. I am waiting on my new cams/valve springs to be able to up the rev limiter to 8k. The only time we have run the car with the 850s we had to keep the limiter stock which made for a short powerband .

 

nice writeup, just look at those brand new tires. i hate that i missed you today. i wanted to ride in that thing.

did you get rid of the FJ?

 

Nice write up Luie-looks like you guys had fun. Cant wait for next years Z days to go at it again...

 

Great write-up. I plan on going with a full-build and JWT 700bbs by year's end.

I noticed you're not running the JWT intercooler, but what looks like the Greddy FMIC; any particular reason you went with that core?

John

 

Same here bro cant wait.
We need to get you out to one of these track event when ever you get a chance.

 

Great write up Luie. Can't wait to "feel" some of that 700bb torque myself

EDIT: What tires do you run at the track (sorry if I missed it)? Luvin the Enkei NT03+M track wheels...

 

Dude same here sorry I missed you.
Yep the car runs like a beast! This car was meant to be on the track, it feels soo good out there.
I feel bad driving it on the street. My car on the street feels like a dog when you put on of those plastic cone things around thier neck

 

tuning wise can you run that boost on pump 91 gas?

 

nice review! look forward to Sharif's. That car has to be a beast. Is that 3301 lbs with you in or out of the car?


slightly off subject, but this is the sorta thing with big vs smaller turbos is kinda what I'm always talking about with turbos and centrifugal SC's. That you get more room for fine tuning the throttle pedal in mid corner with a wider range of pedal motion that won't summon up too much boost over a narrower range of throttle positions like smaller turbos might

Sure you can drive through a corner fast with an early spooling turbo and it works fine, but it's a little more difficult and not as confident inspiring. One of many reasons why the porsche GT3 is a better track car than a 911 turbo

 

That with me out the car.
So true about the GT3 comment.

 

I never had a problem pushing quick spooling power pushing HARD around corners but thats just me. Everybody has a different "flavor" per say, Id rather have the wider powerband, but in Luie's lead foot case, the delay works out for him...Im interested in how Sharif would compare the BB700 to his old Greddy set-up, quicker spool for 700? likely pretty similar midrange with the top end advantage going to Greddy Id imagine but we'll see what he says.

ecit-Luie OT but you still coming to our track day (1/4) this Friday?