| Author | Message | ||
| Matt Morgan (Kermit)
Junior Member Username: Kermit Post Number: 153 Registered: 8-2001 |
Well, after checking and retesting, I've found the same results every time. The Stock TB, bored to 70mm flows well with the Bosch distributor. I can't wait to get one tuned on the Dyno. IMO, the main problem now is the inherent design of the plate that senses air flow. Not a lot can be done with that, as I can see. Unfortunately, the vacuum it takes to operate it is always going to be a restriction. All things considered, I think it is an excellent improvement in flow, and the resulting performance. Here's one for the DYI's: In testing , I found there to be a 2% increase in flow with the air cleaner top removed. After checking for clearance issues, I found the top could be easily raised by 1/2", and by spaceing the top up, it increased flow 2%, while the intake temp dropped 3 degrees. the spacer can easily be made, and as long as it seals, it is an easy way to increase power. Enjoy the ride. | ||
| Matt Morgan (Kermit)
Junior Member Username: Kermit Post Number: 152 Registered: 8-2001 |
FYI: The latest part of the flow bench saga is to space the air cleaner top up about .5". I found that the differance in flow with it on, and without, to resulted in a 2% loss in flow with it. I noted how shallow the one end is, and with the K&N filter in place, removeing the top tin improved the flow. I'll post the rest very soon, probably tomorrow. | ||
| Matt Morgan (Kermit)
Junior Member Username: Kermit Post Number: 151 Registered: 8-2001 |
The plenum can be easily opened to 70mm without any trouble, and sealed with an O ring set into the 2/3rd's into the TB houseing. this is the same style sealing that HD aftermarket carbs use, without any problems ( and they do move around, as the "V" grows with heat. It will be a true bolt on, with plenum blending easily done by the DYI. Jeff,the low RPM performance should not be changed IMO, as the Air flow sensor plate still works as before, so the mixture will be fine, perhaps with a bit of adjustment. As to the TB not haveing cast bosses for the TPS, they can be welded on,prior to machining. Russ I'm on the same path when it comes to the feed tude between the Distributor, and TB. IMO, something smooth as possible, preferably insulated shoule do the trick. I have some stuf on the way. I'll let you know. | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 458 Registered: 2-2003 |
This is really interesting. I guess I am interested in Jeff's concern about low end on the K-jet. I think the later models with the TPS and frequency valve would cover the airflow variation in the fuel control pressure. There is no doubt that the high end would be better, and I've always heard that the Bosch fuel distributor had a lot more delivery capability left.. One of my wild hair ideas was to fab a smooth fiberglass or aluminum replacement for the flex hose to reduce resistance to airflow over the corrugated rubber hose - kind of an upstream port and polish applied the air channel. Should be very easy to fabricate. (Kermit - I'll expect a free coke if you sell this  ) The idea is to keep the air flowing as fast and smooth as possible. Kermit - should be easy enough to check compatability with the Kjet- just open up the plenum port, bolt on and go. I also wonder if the 928 guys have any tricks? As I said, Ed Maszula has been running his tb enlargement ad for a long time so there must be something to it. Looking forward to the results best rt | ||
| jeff ryerson (Atheyg)
Member Username: Atheyg Post Number: 441 Registered: 8-2002 |
Thanks for the info Matt, It will be interesting to have further tests. Unfortuntely the Tb I purchased is from a 308i which has no mount on the side for the TPS, it was supposed to be from a 328, so I will be looking for another to modify. The concern I have with the boring is bottom end hesitation, I am sure the top end will benefit from this. | ||
| Matt Morgan (Kermit)
Junior Member Username: Kermit Post Number: 150 Registered: 8-2001 |
Ok, Jeff, I'm back.Sorry for the delay, as flowbenching can eat up the hours. I have just completed an extensive test of the entire 3084V injection from air cleaner on thru. Here are the following results: In a back to back test, with the Stock Bosch Fuel distributor in place a part of the package (sans air cleaner)a change from a stock 65mm TB to a bored and modified unit with a 70mm throttle plate increased the flow from 80% of test HG, to 90%. I reran the test with only the TB's on the bench, and found an identical increase in flow. I would conclude that the stock system was not necessarily "maxed out" at 65mm, and that the total package will flow more. I'll have pics up on my site soon. Now we know. | ||
| jeff ryerson (Atheyg)
Member Username: Atheyg Post Number: 429 Registered: 8-2002 |
Great Matt, let us know the results! | ||
| Matt Morgan (Kermit)
Junior Member Username: Kermit Post Number: 149 Registered: 8-2001 |
Jeff, I am in the last leg of finishing the new oversize TB, @ 70mm diameter bore. Initial tests late last night showed a comparative 71 % of flow range used with the 65mm, and right after, the 70mm tested at 89% of the same setting. This will be up on my site very soon, as well as many of the brackets, etc to use an Electromotive injection, or for that matter, any aftermarket injection that uses the same Throttle Position Sensor. I'll also be includeing an easy to mount Idle Control Motor that is much simpler that what is available now. By the days end I should know how well it will work with the stock Bosch as well, for those who wish to go that route as a way of improveing power, on a smaller budget, thus allowing more left for other mods. | ||
| jeff ryerson (Atheyg)
Member Username: Atheyg Post Number: 427 Registered: 8-2002 |
Russ, Your carb project seems like a good way to go, even if you don't get a major increase in HP you should have a great difference in throttle response I am really not expecting much by doing a TB mod but its cheap and easy and if I get 5-8hp I would be happy | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 441 Registered: 2-2003 |
It looks to me that you may could easily enlarge the plenum opening to match the enlarged tb without moving the plenum studs. Should help mid and upper range flows. I'm told that a good plenum cleaning makes a difference as well. Good luck and let us know! | ||
| jeff ryerson (Atheyg)
Member Username: Atheyg Post Number: 426 Registered: 8-2002 |
Russ Yes, I've purchased a used one, I was going to either have it enlarged or ported and polished. I dont have an extra plenum so I really don't want to mess with enlarging it in case this doesn't work out so I can reinstall my old TB, I was hoping the plenum hole may be a little larger than the TB, looks like I'll just have a custom port/polish job Regards Jeff | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 440 Registered: 2-2003 |
Yes. Sounds identical to Matt's 308 measurements. Are you going to have your tb enlarged? I see the Mr Maszula's ad in Excellence to do that. | ||
| jeff ryerson (Atheyg)
Member Username: Atheyg Post Number: 425 Registered: 8-2002 |
Thanks Russ, Is the Throttle Body the same diameter? | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 439 Registered: 2-2003 |
3.2 plenum opening measured at 65mm today hope this helps rt | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 426 Registered: 2-2003 |
My 3.2 plenum and tb are in a box at the shop. Will try to measure them next week. best rt | ||
| jeff ryerson (Atheyg)
Member Username: Atheyg Post Number: 412 Registered: 8-2002 |
Thanks Matt & Paul What I was trying to figure out was if the plenum hole is the same size as the throttle body | ||
| Paul Sloan (Sloan83qv)
Member Username: Sloan83qv Post Number: 635 Registered: 3-2001 |
Jeff, I would contact JRV at: http://www.pinnaclemotorsports.com as he would know without a question. Paul | ||
| Matt Morgan (Kermit)
Junior Member Username: Kermit Post Number: 148 Registered: 8-2001 |
Jeff, I have found that the 4V, and 2V use virtually he same TB for 308's. I would expect that as I notice that they both have an almost identical plenum (2V runners will bolt to a 4V plenum, and of course the reverse is true). My Measurements are 65mm throttle plate on both, and I would be suprized if the 328 is a different size. | ||
| jeff ryerson (Atheyg)
Member Username: Atheyg Post Number: 408 Registered: 8-2002 |
Does anyone know the size of the opening for the Throttle Body on the intake plenum for a 3.2V8? Also do you know the inside diameter of the throttle body? Thanks |